Both β-Ga2O3 and wurtzite AlN have wide bandgaps of 4.5–4.9 and 6.1 eV, respectively. We calculated the in-plane lattice mismatch between the (−201) plane of β-Ga2O3 and the (0002) plane of AlN, which was found to be 2.4%. This is the smallest mismatch between β-Ga2O3 and binary III-nitrides which is beneficial for the formation of a high quality β-Ga2O3/AlN heterojunction. However, the valence and conduction band offsets (VBO and CBO) at the β-Ga2O3/AlN heterojunction have not yet been identified. In this study, a very thin (less than 2 nm) β-Ga2O3 layer was deposited on an AlN/sapphire template to form the heterojunction by pulsed laser deposition. High-resolution X-ray photoelectron spectroscopy revealed the core-level (CL) binding energies of Ga 3d and Al 2p with respect to the valence band maximum in individual β-Ga2O3 and AlN layers, respectively. The separation between Ga 3d and Al 2p CLs at the β-Ga2O3/AlN interface was also measured. Eventually, the VBO was found to be −0.55 ± 0.05 eV. Consequently, a staggered-gap (type II) heterojunction with a CBO of −1.75 ± 0.05 eV was determined. The identification of the band alignment of the β-Ga2O3/AlN heterojunction could facilitate the design of optical and electronic devices based on these and related alloys.

1.
C. G.
Van de Walle
and
J.
Neugebauer
,
Nature
423
,
626
(
2003
).
2.
B.
Janjua
,
H.
Sun
,
C.
Zhao
,
D. H.
Anjum
,
D.
Priante
,
A. A.
Alhamoud
,
F.
Wu
,
X.
Li
,
A. M.
Albadri
,
A. Y.
Alyamani
,
M. M.
El-Desouki
,
T. K.
Ng
, and
B. S.
Ooi
,
Opt. Express
25
,
1381
(
2017
).
3.
T. D.
Moustakas
and
R.
Paiella
,
Rep. Prog. Phys.
80
,
106501
(
2017
).
4.
N.
Alfaraj
,
S.
Mitra
,
F.
Wu
,
I.
Ajia
,
B.
Janjua
,
A.
Prabaswara
,
R. A.
Aljefri
,
H.
Sun
,
T. K.
Ng
,
B. S.
Ooi
,
I. S.
Roqan
, and
X.
Li
,
Appl. Phys. Lett.
110
,
161110
(
2017
).
5.
M.
Higashiwaki
,
K.
Sasaki
,
A.
Kuramata
,
T.
Masui
, and
S.
Yamakoshi
,
Appl. Phys. Lett.
100
,
013504
(
2012
).
6.
M. A.
Mastro
,
A.
Kuramata
,
J.
Calkins
,
J.
Kim
,
F.
Ren
, and
S. J.
Pearton
,
ECS J. Solid State Sci. Technol.
6
,
P356
(
2017
).
7.
K.
Konishi
,
K.
Goto
,
H.
Murakami
,
Y.
Kumagai
,
A.
Kuramata
,
S.
Yamakoshi
, and
M.
Higashiwaki
,
Appl. Phys. Lett.
110
,
103506
(
2017
).
8.
J.
Kim
,
S.
Oh
,
M.
Mastro
, and
J.
Kim
,
Phys. Chem. Chem. Phys.
18
,
15760
(
2016
).
9.
A. M.
Armstrong
,
M. H.
Crawford
,
A.
Jayawardena
,
A.
Ahyi
, and
S.
Dhar
,
J. Appl. Phys.
119
,
103102
(
2016
).
10.
Z.
Liu
,
T.
Yamazaki
,
Y.
Shen
,
T.
Kikuta
,
N.
Nakatani
, and
Y.
Li
,
Sens. Actuators, B
129
,
666
(
2008
).
11.
A.
Kuramata
,
K.
Koshi
,
S.
Watanabe
,
Y.
Yamaoka
,
T.
Masui
, and
S.
Yamakoshi
,
Jpn. J. Appl. Phys., Part 1
55
,
1202A2
(
2016
).
12.
M.
Higashiwaki
,
K.
Sasaki
,
A.
Kuramata
,
T.
Masui
, and
S.
Yamakoshi
,
Phys. Status Solidi A
211
,
21
(
2014
).
13.
R. C.
Powell
,
N.-E.
Lee
,
Y.-W.
Kim
, and
J. E.
Greene
,
J. Appl. Phys.
73
,
189
(
1993
).
14.
S.
Nakagomi
and
Y.
Kokubun
,
J. Cryst. Growth
349
,
12
(
2012
).
15.
M. M.
Muhammed
,
M.
Peres
,
Y.
Yamashita
,
Y.
Morishima
,
S.
Sato
,
N.
Franco
,
K.
Lorenz
,
A.
Kuramata
, and
I. S.
Roqan
,
Appl. Phys. Lett.
105
,
042112
(
2014
).
16.
M. J.
Tadjer
,
M. A.
Mastro
,
N. A.
Mahadik
,
M.
Currie
,
V. D.
Wheeler
,
J. A.
Freitas
, Jr.
,
J. D.
Greenlee
,
J. K.
Hite
,
K. D.
Hobart
,
C. R.
Eddy
, Jr.
, and
F. J.
Kub
,
J. Electron. Mater.
45
,
2031
(
2016
).
17.
T.
Oshima
,
T.
Okuno
, and
S.
Fujita
,
Jpn. J. Appl. Phys., Part 1
46
,
7217
(
2007
).
18.
A. J.
Green
,
K. D.
Chabak
,
E. R.
Heller
,
R. C.
Fitch
,
M.
Baldini
,
A.
Fiedler
,
K.
Irmscher
,
G.
Wagner
,
Z.
Galazka
,
S. E.
Tetlak
,
A.
Crespo
,
K.
Leedy
, and
G. H.
Jessen
,
IEEE Electron Device Lett.
37
(
7
),
902
(
2016
).
19.
Z. W.
Chen
,
K.
Nishihagi
,
X.
Wang
,
K.
Saito
,
T.
Tanaka
,
M.
Nishio
,
M.
Arita
, and
Q. X.
Guo
,
Appl. Phys. Lett.
109
,
102106
(
2016
).
20.
W.
Wei
,
Z.
Qin
,
S.
Fan
,
Z.
Li
,
K.
Shi
,
Q.
Zhu
, and
G.
Zhang
,
Nanoscale Res. Lett.
7
,
562
(
2012
).
21.
S. H.
Chang
,
Z. Z.
Chen
,
W.
Huang
,
X. C.
Liu
,
B. Y.
Chen
,
Z. Z.
Li
, and
E. W.
Shi
,
Chin. Phys. B
20
,
116101
(
2011
).
22.
P. H.
Carey
,
F.
Ren
,
D. C.
Hays
,
B. P.
Gila
,
S. J.
Pearton
,
S.
Jang
, and
A.
Kuramata
,
Vacuum
142
,
52
(
2017
).
23.
P. H.
Carey
,
F.
Ren
,
D. C.
Hays
,
B. P.
Gila
,
S. J.
Pearton
,
S.
Jang
, and
A.
Kuramata
,
J. Vac. Sci. Technol., B
35
,
041201
(
2017
).
24.
K. D.
Leedy
,
K. D.
Chabak
,
V.
Vasilyev
,
D. C.
Look
,
J. J.
Boeckl
,
J. L.
Brown
,
S. E.
Tetlak
,
A. J.
Green
,
N. A.
Moser
,
A.
Crespo
,
D. B.
Thomson
,
R. C.
Fitch
,
J. P.
McCandless
, and
G. H.
Jessen
,
Appl. Phys. Lett.
111
,
012103
(
2017
).
25.
C.
Kranert
,
C.
Sturm
,
R.
Schmidt-Grund
, and
M.
Grundmann
,
Sci. Rep.
6
,
35964
(
2016
).
26.
M.
Kubal
,
Surf. Interface Anal.
31
,
987
(
2001
).
27.
J.
Áhman
,
G.
Svensson
, and
J.
Albertsson
,
Acta Crystallogr., Sect. C: Cryst. Struct. Commun.
52
,
1336
(
1996
).
28.
F.-P.
Yu
,
S.-L.
Ou
, and
D.-S.
Wuu
,
Opt. Mater. Express
5
,
1240
(
2015
).
29.
L. M.
Garten
,
A.
Zakutayev
,
J. D.
Perkins
,
B. P.
Gorman
,
P. F.
Ndione
, and
D. S.
Ginley
,
MRS Commun.
6
,
348
(
2016
).
30.
H.
Sun
,
Y.
Park
,
K.-H.
Li
,
C. T.
Castanedo
,
A.
Alowayed
,
T.
Detchprohm
,
R.
Dupuis
, and
X.
Li
,
Appl. Phys. Lett.
111
,
122106
(
2017
).
31.
M.
Tangi
,
P.
Mishra
,
C.
Tseng
,
T. K.
Ng
,
M. N.
Hedhili
,
D. H.
Anjum
,
M. S.
Alias
,
N.
Wei
,
L.
Li
, and
B. S.
Ooi
,
ACS Appl. Mater. Interfaces
9
,
9110
(
2017
).
32.
E. A.
Kraut
,
R. W.
Grant
,
J. R.
Waldrop
, and
S. P.
Kowalczyk
,
Phys. Rev. Lett.
44
,
1620
(
1980
).
33.
A.
Segura
,
L.
Artús
,
R.
Cuscó
,
R.
Goldhahn
, and
M.
Feneberg
,
Phys. Rev. Mater.
1
,
024604
(
2017
).
34.
C. G.
Van de Walle
and
J.
Neugebauer
,
Appl. Phys. Lett.
70
,
2577
(
1997
).
35.
S.
Wei
and
A.
Zunger
,
Appl. Phys. Lett.
69
,
2719
(
1996
).
36.
S.
Rafique
,
L.
Han
,
S.
Mou
, and
H.
Zhao
,
Opt. Mater. Express
7
,
3561
(
2017
).
37.
S. I.
Stepanov
,
V. I.
Nikolaev
,
V. E.
Bougrov
, and
A. E.
Romanov
,
Rev. Adv. Mater. Sci.
44
,
63
(
2016
), available at http://www.ipme.ru/e-journals/RAMS/no_14416/06_14416_stepanov.pdf.
38.
S.
Vitanov
, “
Simulation of high electron mobility transistors
,” Ph.D. dissertation, Technischen Universität Wien,
2010
.
You do not currently have access to this content.