Nanome e -Scale La e al p−n Junc ions in G aphene/α-RuCl3
He e os uc u es
Daniel J. Rizzo,
□
Sa a Shabani,
□
Bja ke S. Jessen,
□
Jin Zhang,
□
Alexande S. McLeod,
Ca men Rubio-Ve du, F ancesco L. Ru a, Ma hew Co h ine, Jiaqiang Yan, Da id G. Mand us,
S ephen E. Nagle , Angel Rubio,*James C. Hone, Co y R. Dean, Abhay N. Pasupa hy,*
and D. N. Baso *
Ci e This: Nano Le . 2022, 22, 1946−1953
Read Online
ACCESS Me ics & Mo e A icle Recommenda ions *
sıSuppo ing In o ma ion
ABSTRACT: The abili y o c ea e nanome e -scale la e al p−n
junc ions is essen ial o he nex gene a ion o wo-dimensional
(2D) de ices. Using he cha ge- ans e he e os uc u e g aphene/α-
RuCl3, we ealize nanoscale la e al p−n junc ions in he icini y o
g aphene nanobubbles. Ou mul ip onged expe imen al app oach
inco po a es scanning unneling mic oscopy (STM) and spec os-
copy (STS) and sca e ing- ype scanning nea -field op ical
mic oscopy (s-SNOM) o simul aneously p obe he elec onic and
op ical esponses o nanobubble p−n junc ions. Ou STM/STS
esul s e eal ha p−n junc ions wi h a band offse o ∼0.6 eV can be
achie ed wi h wid hs o ∼3 nm, gi ing ise o elec ic fields o o de
108V/m. Concu en s-SNOM measu emen s alida e a poin -
sca e e o malism o modeling he in e ac ion o su ace plasmon
pola i ons (SPPs) wi h nanobubbles. Ab ini io densi y unc ional heo y (DFT) calcula ions co obo a e ou expe imen al da a and
e eal he dependence o cha ge ans e on laye sepa a ion. Ou s udy p o ides expe imen al and concep ual ounda ions o
gene a ing p−n nanojunc ions in 2D ma e ials.
KEYWORDS: scanning unneling mic oscopy, scanning unneling spec oscopy, scanning nea -field op ical mic oscopy, plasmons,
wo-dimensional ma e ials, cha ge ans e
■INTRODUCTION
Nanoscale la e al p−n junc ions in g aphene p esen p omising
ou es o in es iga ing undamen al quan um phenomena such
as And ee eflec ion,
1,2
whispe ing galle y mode esona o s,
3,4
quan um do s,
5−9
Veselago lensing,
10,11
and pho onic
c ys als.
12
The abili y o ealize nanoa chi ec u es capable o
hos ing hese p ope ies elies on p ecise con ol o e he
la e al p−n junc ion size, ideally down o a omic leng h scales.
Despi e he po en ial ad an ages o ailo ed nanome e
junc ions, a emp s o ealize sha p and clean in e acial
junc ions in g aphene-based de ices ha e been limi ed by he
p ecision o nanoli hog aphic echniques (i.e., >20 nm)
11,13
and lack he nominal po en ial p ofile o yielding high-quali y
de ices. Con en ional echniques such as local back ga ing,
13,14
ion implan a ion,
15,16
and ada oms
17
a e p ac ically challenging
o implemen and can be accompanied by an inc ease in
diso de , educ ion in mobili y, and su ace con amina ion.
Mo eo e , he maximum cha ge ca ie densi y achie able wi h
hese app oaches is ypically limi ed o less han 5 ×1012
cm−2,
18,19
es ic ing he po en ial g adien s accessible wi h
hese echniques.
Recen heo e ical
20,21
and expe imen al
22−25
wo k on
g aphene/α-RuCl3he e os uc u es demons a es ha he
Di ac-poin ene gy (EDi ac) in g aphene will expe ience a
massi e shi (∼0.6 eV) due o wo k unc ion-media ed
in e laye cha ge ans e wi h he unde lying α-RuCl3. While
anspo measu emen s sugges a high deg ee o in e laye
cha ge ans e
23
in g aphene/α-RuCl3he e os uc u es (>1013
cm−2), hey ha e no e ealed he la e al dimensions o his
cha ging p ocess. On he o he hand, analysis o he plasmonic
beha io o g aphene/α-RuCl3in he icini y o nanobubbles
sugges s ha bounda ies be ween highly doped and p is ine
g aphene a e no wide han 50 nm.
22
Raman maps conduc ed
on hese he e os uc u es p oduce simila cons ain s on he
maximum size o la e al cha ge modula ion bounda ies.
24
Recei ed: No embe 27, 2021
Re ised: Feb ua y 9, 2022
Published: Feb ua y 28, 2022
Le e pubs.acs.o g/NanoLe
© 2022 The Au ho s. Published by
Ame ican Chemical Socie y 1946
h ps://doi.o g/10.1021/acs.nanole .1c04579
Nano Le . 2022, 22, 1946−1953
Downloaded ia UNIV DEL PAIS VASCO on May 25, 2022 a 17:37:26 (UTC).
See h ps://pubs.acs.o g/sha ingguidelines o op ions on how o legi ima ely sha e published a icles.
Howe e , a de ailed unde s anding o he nanoscale spa ial
dependence o in e laye cha ge ans e be ween g aphene and
α-RuCl3necessi a es use o a high- esolu ion local p obe.
In o de o elucida e he in insic la e al and e ical leng h
scales associa ed wi h in e laye cha ge ans e in g aphene/α-
RuCl3he e os uc u es, we employ wo complemen a y
imaging and spec oscopic echniques: scanning unneling
mic oscopy and spec oscopy (STM/STS) and sca e ing- ype
scanning nea -field op ical mic oscopy (s-SNOM). STM and
STS a e ideal p obes o s udying la e al junc ion in e aces
(e.g., p−n, p−p′,p−i−p, e c.) wi h a omic esolu ion and
p o ide in o ma ion abou he local elec onic s uc u e (in
pa icula , EDi ac in g aphene). On he o he hand, s-SNOM
uses hyb id ligh −ma e modes known as su ace plasmon
pola i ons (SPPs) o p obe he local conduc i i y in g aphene.
This mul imessenge expe imen al app oach p o ides a
mul i ace ed iew o he undamen al leng h scales associa ed
wi h in e laye cha ge ans e as encoded in bo h he
elec onic and plasmonic esponses o g aphene/α-RuCl3.
We use nanobubbles ha a ise spon aneously a he
g aphene/α-RuCl3he e os uc u e in e ace du ing ab ica ion
as a es bed o p obing he in-plane and ou -o -plane beha io
o in e laye cha ge ans e . Diffe en ial conduc i i y (dI/dV)
maps and poin spec oscopy pe o med a he bounda y o
nanobubbles e eal ha highly p-doped and in insically n-
doped g aphene a e sepa a ed by a la e al dis ance o ∼3nm
and e ically by ∼0.5 nm, gene a ing in e nal fields on he
o de o 108V/m. In addi ion, he apid change in he
g aphene conduc i i y in he icini y o nanobubbles ac s as a
ha d plasmonic ba ie ha eflec s SPPs gene a ed du ing s-
SNOM measu emen s, as obse ed p e iously.
22
The esul s o
STS measu emen s in o m ou in e p e a ion o he s-SNOM
da a and pe mi us o u he de elop ou model o he
complex- alued nea -field signal associa ed wi h nanobubble-
sca e ed SPPs using a pe u ba i e poin -sca e e app oach.
Ou esul s a e well suppo ed by fi s -p inciples densi y
unc ional heo y (DFT) calcula ions, which e eal he o igin
o he sha p spa ial p ofile o in e laye cha ge ans e a he
bounda y o nanobubbles.
■RESULTS AND DISCUSSION
The g aphene/α-RuCl3he e os uc u es s udied he ein we e
ab ica ed using d y ans e echniques om componen s
isola ed using ex olia ion om single-c ys al sou ces (see
Me hods and Figu e S1 o ab ica ion p ocess). The esul ing
he e os uc u e consis s o la ge egions o g aphene o ming a
fla in e ace wi h he unde lying α-RuCl3,whicha e
occasionally in e up ed by g aphene nanobubbles (Figu e
1A) (see Figu e S2 o STM opog aphic o e iew).
A high-magnifica ion opog aphic STM image o a cha ac e -
is ic g aphene nanobubble is shown in Figu e 1B. As obse ed
wi h STM opog aphy, he ypical heigh s o nanobubbles
s udied in his wo k we e be ween 1 o 3 nm, while he adius
anged om 20 o 80 nm. Topog aphic images collec ed wi h
an a omic o ce mic oscope (AFM) used du ing s-SNOM
measu emen s yield simila nanobubble dimensions (Figu e
S2). On he o he hand, nea -field images o hese same
nanobubbles collec ed using s-SNOM e eal la ge ci cula
ea u es ha ex end o e la e al dis ances o se e al hund ed
nanome e s (Figu e 1C). The oscilla o y na u e o he nea -
field signal mo ing adially om nanobubbles is consis en
wi h he p esence o SPPs ha a e ei he being launched o
eflec ed om hese loca ions, gi ing ise o modula ions in he
nea -field signal ha ex end a beyond he nanobubble a ea. I
has been sugges ed ha hese plasmonic ea u es a ise due o
discon inui ies in he g aphene conduc i i y associa ed wi h
local modula ion o cha ge ca ie densi y,
22
hough he p ecise
na u e o his p ofile demands u he sc u iny wi h STM and
STS.
In o de o gain insigh in o he spa ial dependence o
in e laye cha ge ans e , we pe o med a se ies o STM and
STS measu emen s in he icini y g aphene nanobubbles
(Figu es 2,S3). Figu e 2A shows wo ep esen a i e poin
spec a collec ed on a fla in e ace o g aphene/α-RuCl3( ed
cu e) and on a nanobubble (blue cu e). The spec um aken
on he nanobubble (blue cu e) is cha ac e is ic o sligh ly
in insically n-doped g aphene since EDi ac is loca ed a −100
meV ela i e o he Fe mi ene gy EF. This spec um ac s as a
e e ence o he p is ine g aphene densi y o s a es. On he
o he hand, he dI/dVspec um on he fla g aphene/α-RuCl3
egion ( ed cu e) away om he nanobubble junc ion shows a
shi in he Di ac poin ene gy o ΔEDi ac = +625 meV ela i e
o p is ine g aphene suspended in he nanobubble. This
massi e shi in EDi ac co esponds o a hole densi y in g aphene
Figu e 1. O e iew o join STM/s-SNOM in es iga ion o
nanobubbles in g aphene/α-RuCl3he e os uc u es. (A) Schema ic
o Di ac-poin ene gy shi be ween nanobubbles and clean fla
in e aces in g aphene/α-RuCl3he e os uc u es. The ∼0.6 eV ene gy
shi akes place o e a la e al leng h scale o ∼3 nm a he bounda y
o nanobubbles, gene a ing effec i e la e al fields o E|| ≈2×108V/m
(0.2 V/nm). Since he p is ine g aphene suspended in he nanobubble
is in insically n-doped, a p−n junc ion is c ea ed a he nanobubble
bounda y. The associa ed jump in he g aphene conduc i i y a he
pe ime e o he nanobubble ac s as a ha d bounda y o eflec ion o
su ace plasmon pola i ons. (B) Cha ac e is ic STM opog aphic
image o a nanobubble (VS= 0.7 V, I = 50 pA). The inse shows he
one-dimensional c oss sec ion o he nanobubble opog aphy. (C)
Cha ac e is ic s-SNOM image o wo nanobubbles shows ci cula
inge pa e ns co esponding o adially p opaga ing su ace plasmon
pola i ons (ω= 1050 cm−1).
Nano Le e s pubs.acs.o g/NanoLe Le e
h ps://doi.o g/10.1021/acs.nanole .1c04579
Nano Le . 2022, 22, 1946−1953
1947
g ea e han 1013 cm−2 esul ing om in e laye cha ge ans e
wi h α-RuCl3. We a ibu e he local minimum close o EF
obse ed o bo h spec a o he ubiqui ous inelas ic unneling
gap ha a ises due o phonon-media ed p ocesses independen
o he g aphene doping le el.
19
This di ec obse a ion o
hea ily p-doped g aphene on α-RuCl3by STM is consis en
wi h he p e ious op ical and anspo s udies
22−25
and
demons a es ha p−n junc ions a e o med a he nanobubble
bounda ies.
To isualize nanobubble p−n junc ions, dI/dVmaps we e
conduc ed a biases co esponding o EDi ac o bo h he
nanobubble and fla in e ace egions (Figu e 2B). The
spec oscopic map conduc ed a −100 mV associa ed wi h
EDi ac o henanobubbleshowsahighLDOSon he
su ounding g aphene/α-RuCl3compa ed o he nanobubble
a ea. A sha p jump in he LDOS is obse ed a he bounda y
be ween hese wo egions ha occu s o e a la e al leng h
scale o app oxima ely 3 nm (g een cu e, Figu e 2C). This is
consis en wi h he expec a ion ha he nanobubble should
ha e a supp essed LDOS a i s EDi ac compa ed o he
su ounding highly doped egions. By he same easoning, a
+525 mV (i.e., EDi ac o he fla g aphene/α-RuCl3in e ace)
he LDOS is enhanced on he nanobubble compa ed o he
su ounding fla g aphene/α-RuCl3 egion. A simila ly ab up
shi in he LDOS a he nanobubble edge is obse ed a his
ene gy (pu ple cu e, Figu e 2C). This beha io is cha ac e -
is ic o a nanome e -scale p−n in e ace in g aphene loca ed a
he nanobubble bounda y. We no e ha hese nanobubble p−
n junc ions esemble quan um do s p e iously shown o hos
quasi-bound s a es
5−9
ha would equi e a spec al esolu ion
beyond wha is achie able in he p esen oom empe a u e
s udy o be isualized.
We hen ex ac ed he po en ial p ofile ac oss he p−n
junc ion and e alua ed i s sha pness. A ep esen a i e dI/dV
line cu is shown in Figu e 2D and ollows he whi e ajec o y
highligh ed in he inse o Figu e 2A. Figu e 2D clea ly shows
ha he local minimum o he Di ac poin shi s ab up ly a he
bounda y o he nanobubble om +525 o −100 mV o e a
leng h scale o only a ew nanome e s. To p o ide in o ma ion
abou he co espondence be ween STM opog aphy and he
shi in EDi ac, we compa e he nanobubble opog aphic c oss-
sec ion (deno ed wi h a whi e do ed line in Figu e 2D) wi h
he posi ion-dependence o EDi ac (solid whi e line). I is
e iden ha he change in he g aphene doping le el occu s
Figu e 2. Elec onic s uc u e cha ac e iza ion o nanobubbles in g aphene/α-RuCl3using STM and STS. (A) Inse : STM opog aphic image o a
g aphene nanobubble (VS= 0.7 V, I = 50 pA). Rep esen a i e dI/dVpoin spec oscopy collec ed o e nanobubbles (blue cu e) and fla
g aphene/α-RuCl3in e aces ( ed cu e) as indica ed by he c osshai s in he inse . Be ween hese wo spec a, EDi ac shi s by 625 meV. (B) dI/dV
maps o a g aphene nanobubble conduc ed a he indica ed biases co esponding o he Di ac poin ene gies on he nanobubble (le panel) and he
fla in e ace ( igh panel) (VAC = 25 mV, I = 50 pA). A supp essed LDOS is obse ed a hose biases associa ed wi h he local Di ac poin ene gy.
(C) Linecu s o he dI/dVmaps shown in (B) ollowing he g een and pu ple lines indica ed on he −100 and 525 mV maps, espec i ely. In bo h
ins ances, he change in he LDOS a he bubble bounda y (indica ed by he black dashed line) akes place o e a la e al leng h o app oxima ely 3
nm. (D) Posi ion-dependen dI/dVpoin spec oscopy collec ed along he do ed whi e ajec o y shown in he inse in (A). The shi in he Di ac
poin ene gy occu s o e a la e al leng h scale o ∼3 nm as indica ed by he egion highligh ed in pa ially anspa en ed and blue. The posi ion-
dependence o he Di ac poin ene gy (solid whi e line) is supe imposed on he opog aphic line cu (do ed whi e line) showing ha he p io has
a much mo e ab up spa ial dependence han he la e . (E) Sample dI/dVpoin spec a collec ed a he h eshold o a g aphene nanobubble
co esponding o he ed and blue highligh ed egion in (D).
Nano Le e s pubs.acs.o g/NanoLe Le e
h ps://doi.o g/10.1021/acs.nanole .1c04579
Nano Le . 2022, 22, 1946−1953
1948
much mo e ab up ly han he heigh p ofile o he nanobubble,
implying ha in e laye cha ge ans e is apidly supp essed
wi h in e laye sepa a ion. The la e al junc ion wid h is
measu ed o be ∼3 nm as indica ed in Figu e 2D. The la e al
wid h o his deple ion egion is oughly 1 o de o magni ude
smalle han p e iously epo ed esul s on s a e-o - he-a spli
back ga e de ices.
13
To p o ide a s ep-by-s ep iew o he
e olu ion o EDi ac ac oss he junc ion, a ew spec a om he
junc ion egion a e shown in Figu e 2E. Once he in e ace o
he nanobubble is eached and he g aphene is sepa a ed om
he unde lying α-RuCl3laye by less ha 1 Å, he minimum
co esponding o he Di ac poin a +525 mV apidly shi s o
lowe biases. Beyond his poin , EDi ac shi s mo e g adually
un il i eaches i s minimum alue o −100 mV. (The
dependence o he shi in EDi ac on he nanobubble heigh is
shown explici ly in Figu e 4D.)
A med wi h he esul s o STM and STS expe imen s, we
now e u n o s-SNOM images conduc ed on g aphene
nanobubbles. Da a we e collec ed on fi e diffe en nano-
bubbles o e a equency ange o 930−2280 cm−1(Figu e 3).
Cha ac e is ic images o he nea -field ampli ude and phase o
ω= 990 cm−1a e shown in Figu e 3A. Immedia ely ou side
he adius o he nanobubble, adial oscilla ions o bo h nea -
field channels decay as a unc ion o dis ance as shown in
Figu e 3C. As expec ed,
22
he spacing be ween inges clea ly
dispe ses wi h equency (Figu e S4). In p inciple, hese inges
could a ise om SPPs gene a ed on and p opaga ing away
om nanobubbles (λp inges), om SPPs gene a ed a he
AFM ip ha eflec om he nanobubble bounda y (λp/2
inges), o om bo h. P e ious wo k on simila he e o-
s uc u es would sugges he nea -field beha io is p ima ily
domina ed by he la e .
22
To defini i ely esol e his ques ion, i is use ul o conside
ha he STS da a p o ides unambiguous e idence ha he
en i e y o he g aphene nanobubble consis s o nominally
undoped g aphene su ounded by highly doped g aphene wi h
a bounda y wid h on he o de o only a ew nanome e s. We
he e o e model he s-SNOM da a o a g aphene nanobubble
as a as e -scanned dipole o e a ci cula conduc i i y
deple ion egion su ounded by a bulk possessing high
conduc i i y in a manne simila o ou p e ious s udy
22
(Figu e 3B, see Suppo ing In o ma ion o model desc ip-
ion). Expanding on his p e ious wo k, we now conside ha
he SPPs gene a ed a he AFM ip du ing s-SNOM
measu emen s may possess a wide ange o wa eleng hs
ela i e o he size o he nanobubble. A one ex eme, he SPP
wa eleng h is much la ge han he nanobubble and can pass
h ough wi h li le o no sca e ing. He e, a maximum in bo h
he nea -field ampli ude and phase is obse ed a he loca ion
immedia ely ou side he nanobubble bounda y. A he o he
ex eme, he SPP wa eleng h is oo small o effec i ely couple
o a fini e-sized ip, supp essing he gene a ion o SPPs. A
in e media e leng h scales whe e he SPP wa eleng h is on he
o de o se e al imes he nanobubble dimensions, plasmonic
eflec ions a e obse ed ha esul in λp/2 inges whose
ampli ude scale as R2
bubble
p
λ
i
k
j
j
jy
{
z
z
z(Rbubble is he nanobubble adius)
(Figu e 3B). In con as o he beha io a la ge λp, he e he
nea -field ampli ude possesses a minimum immedia ely ou side
he de ec , while he phase has a maximum. A compa ison o
he expe imen al and simula ed nea -field images shown in
Figu e 3A,B sugges s ha ou expe imen akes place in his
in e media e egime whe e plasmonic eflec ions gi e ise o
λp/2 inges ha gene a e an ampli ude minimum and phase
maximum a he nanobubble bounda y (indica ed by he black
dashed boxed egion in Figu e 3B). In p inciple, λp inges
could exis concu en ly as a esul o ligh sca e ing di ec ly
om acuum in o he g aphene om he nanobubble i sel .
Such inges would ha e a sys ema ic angula -dependen nea -
field signal en o ced by he angle o he inciden ligh p ojec ed
on o he 2D plane. Since a sys ema ic angula dependence is
nei he obse ed in nea -field ampli ude no phase (Figu e S4),
Figu e 3. Cha ac e iza ion o he plasmonic esponse o nanobubbles using s-SNOM. (A) s-SNOM S3ampli ude ( op panel) and Φ3phase
(bo om panel) collec ed in he icini y o a g aphene nanobubble (ω= 990 cm−1). The bubble pe ime e is indica ed in each image wi h a whi e
and black ci cle, espec i ely. A cha ac e is ic inge pa e n is obse ed in bo h he nea -field ampli ude and phase emana ing adially om he
bubble. (B) Simula ed nea -field ampli ude ( op panel) and phase (bo om panel) based on a as e -scanned dipole o e a conduc i i y de ec wi h
fixed adius Rbubble and a a iable SPP wa eleng h λp. The adial dependence /Rbubble o bo h ampli ude and phase a e shown. The black a ows and
black dashed box enclose he egime o λp/Rbubble ha esembles he expe imen al da a. (C) Radial line cu s o he images shown in (A) a e aged
o e hal annuli wi h hicknesses o Δ = 10 nm. The g ay e ical lines indica e he bounda ies o he nanobubble. On he basis o a model ha
ea s he nanobubble as a poin sca e e , he adial dependence o he expe imen al nea -field ampli ude and phase is simul aneously fi o he eal
and imagina y componen s o −A[H1
(1)(qp )]2, espec i ely (H1
(1) is he Hankel unc ion o fi s kind o o de one, qpis he complex SPP
wa e ec o , is he adial coo dina e, and Ais a complex ampli ude). (D) The co esponding dispe sion o SPPs emana ing om fi e diffe en
nanobubbles is ex ac ed using he fi ing p ocedu e desc ibed in (C).
Nano Le e s pubs.acs.o g/NanoLe Le e
h ps://doi.o g/10.1021/acs.nanole .1c04579
Nano Le . 2022, 22, 1946−1953
1949
we exclude he possibili y ha λp inges a e subs an ially
con ibu ing o he obse ed SPP oscilla ions.
An app oxima e ep esen a ion o he adial dependence o
he nea -field ampli ude can be de i ed by pe u ba i ely
ea ing he nanobubble as a poin sca e e . This is a 2D
analogue o Rayleigh sca e ing and may be use ul o analysis
o SPP dispe sions in a manne analogous o quasipa icle
in e e ence (QPI) o 2D elec onic s a es.
26,27
Wi hin his
amewo k, he sca e ed pola i on field is used as a p oxy o
he nea -field signal and has he unc ional o m o
−A[H1
(1)(qp )]2, (he e, H1
(1) is he Hankel unc ion o he
fi s kind o o de one, qp=q1+iq2is he complex SPP
wa e ec o , is he adial coo dina e, and Ais a complex
scaling ac o ) (see Suppo ing In o ma ion o ull de i a ion).
The eal and imagina y componen s o his unc ion a e
simul aneously fi o he nea -field ampli ude and phase,
espec i ely, using Aand qpas fi ing pa ame e s. The esul ing
model line p ofiles ai h ully ep oduce he expe imen al da a
(Figu e 3C). Repea ing his fi ing p ocedu e o all
expe imen al equencies ωand all fi e bubbles yields he
SPP dispe sion ω(q1)(Figu e 3D). The shape o he
expe imen al dispe sion is consis en wi h SPPs p opaga ing
in highly doped g aphene.
Bo h expe imen al STM/STS and s-SNOM da a p o ide
co obo a ing e idence ha in e laye cha ge ans e be ween
g aphene and α-RuCl3is elimina ed in nanobubbles as a esul
o <1 nm o in e laye sepa a ion. We now inqui e in o he
p ecise mechanism by which his cha ge ans e akes place
and how i is supp essed in nanobubbles h ough a se ies o
DFT calcula ions on model g aphene/α-RuCl3he e os uc-
u es. Specifically, we explo ed he ole o an in e media e
acuum egion be ween he wo laye s a ying om 0 o 5 Å
abo e he equilib ium sepa a ion (Figu e 4A). As epo ed
p e iously,
22
he shi in EDi ac o he g aphene/α-RuCl3
he e os uc u e wi h an equilib ium in e laye sepa a ion
(hmin = 3.3 Å) is obse ed o be 0.54 eV (Figu e 4B), which
is in good ag eemen wi h he expe imen al da a on fla
in e ace egions. Expanding on his p e ious esul , we show
ha he heo e ical shi in EDi ac effec i ely disappea s once a
acuum space laye o jus Δh=h−hmin = 5 Å is in oduced
(Figu e 4C), e ealing a apid decay in he in e laye cha ge
ans e wi h laye sepa a ion. The heo e ical dependence o
ΔEDi ac a in e media e in e laye sepa a ions shows a apid
jump o Δh< 1 Å ollowed by a mo e g adual decay in he
in e laye cha ge ans e a la ge sepa a ions (Figu e 4D).
The expe imen al coun e pa o his da a can be ex ac ed
om Figu e 2D o isualize ΔEDi ac as a unc ion o he
in e laye sepa a ion be ween g aphene and α-RuCl3. He e,
ΔEDi ac is ob ained om he local minima (o cu a u e
maxima when EDi ac p esen s as a shoulde ) o each dI/dV
spec um aken a a known heigh abo e he fla egion. Figu e
4D demons a es ha he beha io o he model DFT
calcula ion mi o s he expe imen al STS: bo h show wo
cha ac e is ic decay leng hs o less han and on he o de o a
ew angs oms, espec i ely. We specula e ha he eme gence
o wo cha ac e is ic leng h scales associa ed wi h in e laye
cha ge ans e a ises due o a dual mechanism in ol ing sho -
ange in e laye unneling and long- ange elec os a ic effec s
be ween he laye s.
The ag eemen be ween heo y and expe imen shows ha
he magni ude o in e laye cha ge ans e is agnos ic o he
su ounding in-plane cha ge and s ain
28
en i onmen (i.e.,
pu ely dependen on he laye sepa a ion). Thus, i would
appea ha he e is li le o no cha ge edis ibu ion in he
g aphene plane ac oss he nanobubble in e ace despi e la ge
diffe ences in he local cha ge ca ie densi y. To unde s and
his, we e u n o he DFT calcula ions o model he e o-
s uc u es wi h a iable acuum space laye s and plo ΔEDi ac
ela i e o he acuum ene gy (g een cu e in Figu e 4D).
F om his, i is clea ha an elec os a ic ba ie compa able o
he offse in EDi ac o ∼0.6 eV eme ges be ween he p is ine
nanobubble and he highly doped g aphene/α-RuCl3 egion.
Ul ima ely, his la ge elec os a ic ba ie en o ces he sha p p−
n junc ions na u ally gene a ed in nanobubbles.
Finally, we conside he influence o sc eening on p−n
nanojunc ions. Poo sc eening in g aphene pe mi s long- ange
Figu e 4. DFT and STM analysis o in e laye cha ge ans e in
g aphene/α-RuCl3he e os uc u es. (A) Side- iew o he g aphene/
α-RuCl3he e os uc u e supe cell used in DFT calcula ions. An
equilib ium in e laye sepa a ion o hmin = 3.3 Å is used o model he
so-called fla in e ace obse ed expe imen ally. To model he cha ge
ans e beha io be ween g aphene and α-RuCl3a he edge o
nanobubbles (whe e he in e laye sepa a ion inc eases g adually),
addi ional calcula ions a e pe o med using in e laye sepa a ions o
Δh=h−hmin = 0.5, 1, 2, 3, 4, and 5 Å. O ange, g een, and g ay
sphe es indica e Ru, Cl, and C a oms, espec i ely. (B) DFT-
calcula ed band s uc u e o a g aphene/α-RuCl3he e os uc u e
wi h maximal cha ge ans e (i.e., h=hmin = 3.3 Å). (C) Band
s uc u e o g aphene/α-RuCl3he e os uc u e wi h h=hmin +5Å,
showing minimal in e laye cha ge ans e . The Fe mi le els a e se o
ze o in (B,C). (D) The shi in EDi ac ela i e o i s alue on he
nanobubble plo ed as a unc ion o in e laye sepa a ion is plo ed o
bo h expe imen al ( ed do s) and heo e ical (blue do s) da a. The
shi in EDi ac ela i e o he acuum ene gy EVac is plo ed wi h a g een
cu e. The apid decay in in e laye cha ge ans e is highligh ed in
o ange, while he subsequen g adual decay is highligh ed in pu ple.
Nano Le e s pubs.acs.o g/NanoLe Le e
h ps://doi.o g/10.1021/acs.nanole .1c04579
Nano Le . 2022, 22, 1946−1953
1950
inhomogeneous po en ials ex ending >100 nm om me allic
con ac s.
29,30
Con a y o his beha io , mu ual doping a he
g aphene/α-RuCl3in e ace leads o he o ma ion o an
in e laye dipole ha is la gely confined o he fi s a omic
laye s o he he e ojunc ion in e ace.
22
The elec os a ics o
his si ua ion a e analogous o a spli ga e de ice, whe e he
la e al leng h scale o he associa ed ba e po en ial nea p−n
junc ions scales wi h he hickness o he ga e dielec ic (can be
subs an ially smalle han 100 nm
13
). In his con ex , he poo
sc eening in g aphene is less ele an o he esul ing minimum
ea u e size han he leng h scale o he unde lying ba e
po en ial. Fo g aphene/α-RuCl3, he effec i e ga e dielec ic
hickness is on he o de o he laye sepa a ion (<1 nm),
pe mi ing nanome e -scale deple ion egions a nanobubble
bounda ies.
■CONCLUSION
We ha e measu ed he elec onic and pho onic beha io o
nanobubbles in g aphene/α-RuCl3he e os uc u es, e ealing
massi e shi s in he local in e laye cha ge ans e o e la e al
leng h scales o only a ew nanome e s. Such na ow p−n
junc ions in g aphene ha e p e iously been inaccessible using
s anda d doping echniques and ha e many po en ial
applica ions o s udying undamen al elec onic s uc u e
p ope ies in g aphene and ela ed ma e ials. A he same ime,
ou esul s demons a e ha wo k unc ion media ed cha ge
ans e is a iable ou e owa d c ea ing nanoscale
conduc i i y ea u es in g aphene ha ac as local plasmon
sca e e s. The insigh s gained in ou DFT calcula ions p o ide
a de ailed unde s anding o he dependence o cha ge ans e
on in e laye sepa a ion and e eal ab up elec os a ic ba ie s
a nanobubble bounda ies ha gi e ise o nanome e p−n
junc ions. This wo k p o ides he expe imen al and concep ual
ounda ion o u u e de ice design, and alida es he use o
in e s i ial laye s in cha ge- ans e he e os uc u es o
p edic i ely influence he local elec onic and plasmonic
beha io .
■METHODS
Expe imen al and heo e ical me hods can be ound in he
Suppo ing In o ma ion.
■ASSOCIATED CONTENT
*
sıSuppo ing In o ma ion
The Suppo ing In o ma ion is a ailable ee o cha ge a
h ps://pubs.acs.o g/doi/10.1021/acs.nanole .1c04579.
Addi ional de ails abou sample ab ica ion, STM and
AFM opog aphy, auxilia y STS and s-SNOM da a,
expe imen al and heo e ical me hods, and de i a ions
o models o he nea -field da a (PDF)
■AUTHOR INFORMATION
Co esponding Au ho s
D. N. Baso −Depa men o Physics, Columbia Uni e si y,
New Yo k, New Yo k 10027, Uni ed S a es;
Email: [email p o ec ed]
Abhay N. Pasupa hy −Depa men o Physics, Columbia
Uni e si y, New Yo k, New Yo k 10027, Uni ed S a es;
Condensed Ma e Physics and Ma e ials Science
Depa men , B ookha en Na ional Labo a o y, Up on, New
Yo k 11973, Uni ed S a es; o cid.o g/0000-0002-2744-
0634; Email: [email p o ec ed]
Angel Rubio −Theo y Depa men , Max Planck Ins i u e o
S uc u e and Dynamics o Ma e and Cen e o F ee-
Elec on Lase Science, 22761 Hambu g, Ge many; Cen e
o Compu a ional Quan um Physics, Fla i on Ins i u e, New
Yo k, New Yo k 10010, Uni ed S a es; Nano-Bio
Spec oscopy G oup, Uni e sidad del País Vasco UPV/EHU,
San Sebas ián 20018, Spain; o cid.o g/0000-0003-2060-
3151; Email: [email p o ec ed]
Au ho s
Daniel J. Rizzo −Depa men o Physics, Columbia Uni e si y,
New Yo k, New Yo k 10027, Uni ed S a es; o cid.o g/
0000-0003-4587-4863
Sa a Shabani −Depa men o Physics, Columbia Uni e si y,
New Yo k, New Yo k 10027, Uni ed S a es
Bja ke S. Jessen −Depa men o Physics and Depa men o
Mechanical Enginee ing, Columbia Uni e si y, New Yo k,
New Yo k 10027, Uni ed S a es; o cid.o g/0000-0001-
8453-6125
Jin Zhang −Theo y Depa men , Max Planck Ins i u e o
S uc u e and Dynamics o Ma e and Cen e o F ee-
Elec on Lase Science, 22761 Hambu g, Ge many;
o cid.o g/0000-0001-7830-3464
Alexande S. McLeod −Depa men o Physics, Columbia
Uni e si y, New Yo k, New Yo k 10027, Uni ed S a es;
P esen Add ess: School o Physics and As onomy,
Uni e si y o Minneso a, Minneapolis, MN 55455
Ca men Rubio-Ve du
−Depa men o Physics, Columbia
Uni e si y, New Yo k, New Yo k 10027, Uni ed S a es
F ancesco L. Ru a −Depa men o Physics and Depa men
o Applied Physics and Applied Ma hema ics, Columbia
Uni e si y, New Yo k, New Yo k 10027, Uni ed S a es
Ma hew Co h ine −Depa men o Ma e ials Science and
Enginee ing, Uni e si y o Tennessee, Knox ille, Tennessee
37996, Uni ed S a es
Jiaqiang Yan −Depa men o Ma e ials Science and
Enginee ing, Uni e si y o Tennessee, Knox ille, Tennessee
37996, Uni ed S a es; Ma e ials Science and Technology
Di ision, Oak Ridge Na ional Labo a o y, Oak Ridge,
Tennessee 37831, Uni ed S a es
Da id G. Mand us −Depa men o Ma e ials Science and
Enginee ing, Uni e si y o Tennessee, Knox ille, Tennessee
37996, Uni ed S a es; Ma e ials Science and Technology
Di ision, Oak Ridge Na ional Labo a o y, Oak Ridge,
Tennessee 37831, Uni ed S a es; o cid.o g/0000-0003-
3616-7104
S ephen E. Nagle −Neu on Sca e ing Di ision, Oak Ridge
Na ional Labo a o y, Oak Ridge, Tennessee 37831, Uni ed
S a es
James C. Hone −Depa men o Mechanical Enginee ing,
Columbia Uni e si y, New Yo k, New Yo k 10027, Uni ed
S a es
Co y R. Dean −Depa men o Physics, Columbia Uni e si y,
New Yo k, New Yo k 10027, Uni ed S a es
Comple e con ac in o ma ion is a ailable a :
h ps://pubs.acs.o g/10.1021/acs.nanole .1c04579
Au ho Con ibu ions
□
D.J.R., S.S., B.S.J. and J.Z. con ibu ed equally. S.S. pe o med
he STM/STS measu emen s. S.S., C.R.-V., and D.J.R.
conduc ed he STS analysis. A.N.P. ad ised STM/STS
measu emen s. D.J.R. pe o med all s-SNOM measu emen s
and analysis. D.N.B. ad ised s-SNOM measu emen s. A.S.M.
Nano Le e s pubs.acs.o g/NanoLe Le e
h ps://doi.o g/10.1021/acs.nanole .1c04579
Nano Le . 2022, 22, 1946−1953
1951
de i ed analy ical o ms o he nea -field sca e ing ampli ude
and simula ed nea -field images. F.L.R. modeled he nea -field
da a. J.Z. and A.R. pe o med all DFT calcula ions and
analyzed he esul s. B.S.J. ab ica ed he de ices and de eloped
he d y s acking p ocedu e wi h α-RuCl3. J.C.H. and C.R.D.
ad ised de ice ab ica ion effo s. M.C., S.E.N., J.Q.Y., and
D.G.M. pe o med g ow h and cha ac e iza ion o α-RuCl3
single c ys als.
No es
The au ho s decla e no compe ing financial in e es .
■ACKNOWLEDGMENTS
Resea ch a Columbia Uni e si y was suppo ed as pa o he
Ene gy F on ie Resea ch Cen e on P og ammable Quan um
Ma e ials unded by he U.S. Depa men o Ene gy (DOE),
Office o Science, Basic Ene gy Sciences (BES), unde Awa d
No DE-SC0019443. Plasmonic nano-imaging a Columbia
Uni e si y was suppo ed by he U.S. Depa men o Ene gy
(DOE), Office o Science, Basic Ene gy Sciences (BES), unde
Awa d No DE-SC0018426. J.Z. and A.R. we e suppo ed by
he Eu opean Resea ch Council (ERC-2015-AdG694097), he
Clus e o Excellence “Ad anced Imaging o Ma e ”(AIM)
EXC 2056-390715994, unding by he Deu sche Fo schungs-
gemeinscha (DFG, Ge man Resea ch Founda ion) unde
RTG 2247, G upos Consolidados (IT1249-19), and SFB925
“Ligh induced dynamics and con ol o co ela ed quan um
sys ems”. J.Z. and A.R. would like o acknowledge Nicolas
Tancogne-Dejean and Lede Xian o ui ul discussions and
also acknowledge suppo by he Max Planck Ins i u e-New
Yo k Ci y Cen e o Non-Equilib ium Quan um Phenomena.
The Fla i on Ins i u e is a di ision o he Simons Founda ion.
J.Z. acknowledges unding ecei ed om he Eu opean Union
Ho izon 2020 esea ch and inno a ion p og amme unde
Ma ie Skłodowska-Cu ie G an Ag eemen 886291 (PeSD-
NeSL). STM suppo was p o ided by he Na ional Science
Founda ion ia G an DMR-2004691. C.R.-V. acknowledges
unding om he Eu opean Union Ho izon 2020 esea ch and
inno a ion p og amme unde he Ma ie Skłodowska-Cu ie
G an Ag eemen 844271. D.G.M. acknowledges suppo om
he Go don and Be y Moo e Founda ion’s EPiQS Ini ia i e,
G an GBMF9069. J.Q.Y. was suppo ed by he U.S.
Depa men o Ene gy, Office o Science, Basic Ene gy
Sciences, Ma e ials Sciences and Enginee ing Di ision. S.E.N.
acknowledges suppo om he U.S. Depa men o Ene gy,
Office o Science, Basic Ene gy Sciences, Di ision o Scien ific
Use Facili ies. Wo k a Uni e si y o Tennessee was suppo ed
by NSF G an 180896.
■REFERENCES
(1) Beenakke , C. W. J. Specula And ee Re lec ion in G aphene.
Phys. Re . Le . 2006,97, 067007.
(2) Ossipo , A.; Ti o , M.; Beenakke , C. W. J. Reen ance E ec in
a G aphene N-P-N Junc ion Coupled o a Supe conduc o . Phys. Re .
B2007,75, 241401.
(3) Zhao, Y.; Wy ick, J.; Na e e , F. D.; Rod iguez-Nie a, J. F.;
Lewandowski, C.; Wa anabe, K.; Taniguchi, T.; Le i o , L. S.;
Zhi ene , N. B.; S oscio, J. A. C ea ing and P obing Elec on
Whispe ing-Galle y Modes in G aphene. Science 2015,348, 672.
(4) Le, T. L.; Nguyen, V. L. Quan i a i e S udy o Elec onic
Whispe ing Galle y Modes in Elec os a ic-Po en ial Induced Ci cula
G aphene Junc ions. J. Phys.: Condens. Ma e 2020,32, 255502.
(5) Lee, J.; Wong, D.; Velasco, J., J .; Rod iguez-Nie a, J. F.; Kahn,
S.; Tsai, H.-Z.; Taniguchi, T.; Wa anabe, K.; Ze l, A.; Wang, F.;
Le i o , L. S.; C ommie, M. F. Imaging Elec os a ically Con ined
Di ac Fe mions in G aphene Quan um Do s. Na . Phys. 2016,12,
1032−1036.
(6) Gu ié ez, C.; B own, L.; Kim, C.-J.; Pa k, J.; Pasupa hy, A. N.
Klein Tunnelling and Elec on T apping in Nanome e-Scale
G aphene Quan um Do s. Na . Phys. 2016,12, 1069−1075.
(7) Gu ié ez, C.; Walkup, D.; Ghaha i, F.; Lewandowski, C.;
Rod iguez-Nie a, J. F.; Wa anabe, K.; Taniguchi, T.; Le i o , L. S.;
Zhi ene , N. B.; S oscio, J. A. In e ac ion-D i en Quan um Hall
Wedding Cake−Like S uc u es in G aphene Quan um Do s. Science
2018,361, 789.
(8) Velasco, J.; Lee, J.; Wong, D.; Kahn, S.; Tsai, H.-Z.; Cos ello, J.;
Umeda, T.; Taniguchi, T.; Wa anabe, K.; Ze l, A.; Wang, F.;
C ommie, M. F. Visualiza ion and Con ol o Single-Elec on
Cha ging in Bilaye G aphene Quan um Do s. Nano Le . 2018,18,
5104−5110.
(9) Pe ei a, J. M.; Mlina , V.; Pee e s, F. M.; Vasilopoulos, P.
Con ined S a es and Di ec ion-Dependen T ansmission in G aphene
Quan um Wells. Phys. Re . B 2006,74, 045424.
(10) Cheiano , V. V.; Fal'ko, V.; Al shule , B. L. The Focusing o
Elec on Flow and a Veselago Lens in G aphene p-n Junc ions. Science
2007,315, 1252.
(11) Lee, G.-H.; Pa k, G.-H.; Lee, H.-J. Obse a ion o Nega i e
Re ac ion o Di ac Fe mions in G aphene. Na . Phys. 2015,11, 925−
929.
(12) Xiong, L.; Fo sy he, C.; Jung, M.; McLeod, A. S.; Sunku, S. S.;
Shao, Y. M.; Ni, G. X.; S e nbach, A. J.; Liu, S.; Edga , J. H.; Mele, E.
J.; Fogle , M. M.; Sh e s, G.; Dean, C. R.; Baso , D. N. Pho onic
C ys al o G aphene Plasmons. Na . Commun. 2019,10, 4780.
(13) Zhou, X.; Ke elsky, A.; Elahi, M. M.; Wang, D.; Habib, K. M.
M.; Sajjad, R. N.; Agniho i, P.; Lee, J. U.; Ghosh, A. W.; Ross, F. M.;
Pasupa hy, A. N. A omic-Scale Cha ac e iza ion o G aphene P−N
Junc ions o Elec on-Op ical Applica ions. ACS Nano 2019,13,
2558−2566.
(14) Ozyilmaz, B.; Ja illo-He e o, P.; E e o , D.; Kim, P. Elec onic
T anspo in Locally Ga ed G aphene Nanocons ic ions. Appl. Phys.
Le . 2007,91, 192107.
(15) Willke, P.; Amani, J. A.; Sin e hau , A.; Thaku , S.; Ko zo , T.;
D uga, T.; Weike , S.; Mai i, K.; Ho säss, H.; Wende o h, M. Doping
o G aphene by Low-Ene gy Ion Beam Implan a ion: S uc u al,
Elec onic, and T anspo P ope ies. Nano Le . 2015,15, 5110−
5115.
(16) Wang, G.; Zhang, M.; Chen, D.; Guo, Q.; Feng, X.; Niu, T.;
Liu, X.; Li, A.; Lai, J.; Sun, D.; Liao, Z.; Wang, Y.; Chu, P. K.; Ding,
G.; Xie, X.; Di, Z.; Wang, X. Seamless La e al G aphene P-N
Junc ions Fo med by Selec i e in Si u Doping o High-Pe o mance
Pho ode ec o s. Na . Commun. 2018,9, 5168−5168.
(17) P a een, C.; Piccinin, S.; Fab is, S. Adso p ion o Alkali
Ada oms on G aphene Suppo ed by he Au/Ni (111) Su ace. Phys.
Re . B 2015,92, 075403.
(18) Dean, C. R.; Young, A. F.; Me ic, I.; Lee, C.; Wang, L.;
So gen ei, S.; Wa anabe, K.; Taniguchi, T.; Kim, P.; Shepa d, K. L.;
Hone, J. Bo on Ni ide Subs a es o High-Quali y G aphene
Elec onics. Na . Nano echnol. 2010,5, 722−726.
(19) Zhang, Y.; B a , V. W.; Wang, F.; Gi i , C.; Yayon, Y.;
Panlasigui, M.; Ze l, A.; C ommie, M. F. Gian Phonon-Induced
Conduc ance in Scanning Tunnelling Spec oscopy o Ga e-Tunable
G aphene. Na . Phys. 2008,4, 627−630.
(20) Biswas, S.; Li, Y.; Win e , S. M.; Knolle, J.; Valen í, R.
Elec onic P ope ies o A-Rucl3in P oximi y o G aphene. Phys. Re .
Le . 2019,123, 237201.
(21) Ge be , E.; Yao, Y.; A ias, T. A.; Kim, E.-A. Ab Ini io
Misma ched In e ace Theo y o G aphene on A-Rucl3: Doping and
Magne ism. Phys. Re . Le . 2020,124, 106804.
(22) Rizzo, D. J.; Jessen, B. S.; Sun, Z.; Ru a, F. L.; Zhang, J.; Yan, J.-
Q.; Xian, L.; McLeod, A. S.; Be kowi z, M. E.; Wa anabe, K.;
Taniguchi, T.; Nagle , S. E.; Mand us, D. G.; Rubio, A.; Fogle , M.
M.; Millis, A. J.; Hone, J. C.; Dean, C. R.; Baso , D. N. Cha ge-
T ans e Plasmon Pola i ons a G aphene/A-Rucl3In e aces. Nano
Le . 2020,20, 8438−8445.
Nano Le e s pubs.acs.o g/NanoLe Le e
h ps://doi.o g/10.1021/acs.nanole .1c04579
Nano Le . 2022, 22, 1946−1953
1952
(23) Zhou, B.; Balgley, J.; Lampen-Kelley, P.; Yan, J. Q.; Mand us,
D. G.; Hen iksen, E. A. E idence o Cha ge T ans e and P oxima e
Magne ism in G aphene-A-Rucl3He e os uc u es. Phys. Re . B 2019,
100, 165426.
(24) Wang, Y.; Balgley, J.; Ge be , E.; G ay, M.; Kuma , N.; Lu, X.;
Yan, J.-Q.; Fe eidouni, A.; Basne , R.; Yun, S. J.; Su i, D.; Ki adai, H.;
Taniguchi, T.; Wa anabe, K.; Ling, X.; Moode a, J.; Lee, Y. H.;
Chu chill, H. O. H.; Hu, J.; Yang, L.; Kim, E.-A.; Mand us, D. G.;
Hen iksen, E. A.; Bu ch, K. S. Modula ion Doping Via a Two-
Dimensional A omic C ys alline Accep o . Nano Le . 2020,20,
8446−8452.
(25) Mashhadi, S.; Kim, Y.; Kim, J.; Webe , D.; Taniguchi, T.;
Wa anabe, K.; Pa k, N.; Lo sch, B.; Sme , J. H.; Bu gha d, M.; Ke n,
K. Spin-Spli Band Hyb idiza ion in G aphene P oximi ized wi h A-
Rucl3 Nanoshee s. Nano Le . 2019,19, 4659−4665.
(26) C ommie, M. F.; Lu z, C. P.; Eigle , D. M. Imaging S anding
Wa es in a Two-Dimensional Elec on Gas. Na u e 1993,363, 524−
527.
(27) Roushan, P.; Seo, J.; Pa ke , C. V.; Ho , Y. S.; Hsieh, D.; Qian,
D.; Richa della, A.; Hasan, M. Z.; Ca a, R. J.; Yazdani, A. Topological
Su ace S a es P o ec ed om Backsca e ing by Chi al Spin Tex u e.
Na u e 2009,460, 1106−1109.
(28) Le y, N.; Bu ke, S. A.; Meake , K. L.; Panlasigui, M.; Ze l, A.;
Guinea, F.; Ne o, A. H. C.; C ommie, M. F. S ain-Induced Pseudo−
Magne ic Fields G ea e Than 300 T in G aphene Nanobubbles.
Science 2010,329, 544−547.
(29) Khomyako , P. A.; S a iko , A. A.; B ocks, G.; Kelly, P. J.
Nonlinea Sc eening o Cha ges Induced in G aphene by Me al
Con ac s. Phys. Re . B 2010,82, 115437.
(30) Muelle , T.; Xia, F.; F ei ag, M.; Tsang, J.; A ou is, P. Role o
Con ac s in G aphene T ansis o s: A Scanning Pho ocu en S udy.
Phys. Re . B 2009,79, 245430.
■NOTE ADDED AFTER ASAP PUBLICATION
This pape was published ASAP on Feb ua y 28, 2022, wi h an
e o in he Figu e 1 cap ion. The co ec ed e sion was
epos ed on Ma ch 9, 2022.
Nano Le e s pubs.acs.o g/NanoLe Le e
h ps://doi.o g/10.1021/acs.nanole .1c04579
Nano Le . 2022, 22, 1946−1953
1953
Recommended by ACS
Ul asha p La e al p–n Junc ions in Modula ion-Doped
G aphene
Jesse Balgley, E ik A. Hen iksen,
e al.
MAY 09, 2022
NANO LETTERS READ
A omic-Scale Cha ac e iza ion o G aphene p–n
Junc ions o Elec on-Op ical Applica ions
Xiaodong Zhou, Abhay N. Pasupa hy,
e al.
JANUARY 28, 2019
ACS NANO READ
Unexpec ed Elec on T anspo Supp ession in a
He e os uc u ed G aphene–MoS2 Mul iple Field-E ec
T ansis o A chi ec u e
Gaia Ciampalini, S e ano Rodda o,
e al.
DECEMBER 23, 2021
ACS NANO READ
Ul a as Unbalanced Elec on Dis ibu ions in
Quasic ys alline 30° Twis ed Bilaye G aphene
Takeshi Suzuki, Iwao Ma suda,
e al.
SEPTEMBER 25, 2019
ACS NANO READ
Ge Mo e Sugges ions >
