The surface electron accumulation layer, surface structure, and surface chemical states of a-plane (nonpolar) and c-plane (polar) InN epitaxial films were investigated. Electrical measurements indicated electron accumulation layers on the surface of both the InN films. Angle-resolved x-ray photoelectron spectroscopy (XPS) measurements indicated a strong band bending at both surfaces, thus confirming the surface electron accumulation. Further XPS analysis of the near-surface chemical states indicated an In adlayer at the surface of c-plane InN and an oxygen adsorbed layer on the a-plane InN. These results suggest different ad-layers to cause the surface electron accumulation on c-plane and a-plane InN.

1.
H.
Lu
,
W. J.
Schaff
,
L. F.
Eastman
, and
C. E.
Stutz
,
Appl. Phys. Lett.
82
,
1736
(
2003
).
2.
I.
Mahboob
,
T. D.
Veal
,
C. F.
McConville
,
H.
Lu
, and
W. J.
Schaff
,
Phys. Rev. Lett.
92
,
036804
(
2004
).
3.
R. E.
Jones
,
K. M.
Yu
,
S. X.
Li
,
W.
Walukiewicz
,
J. W.
Ager
,
E. E.
Haller
,
H.
Lu
, and
W. J.
Schaff
,
Phys. Rev. Lett.
96
,
125505
(
2006
).
4.
D.
Segev
and
C. G.
Van de Walle
,
Europhys. Lett.
76
,
305
(
2006
).
5.
C. L.
Wu
,
H. M.
Lee
,
C. T.
Kuo
,
C. H.
Chen
, and
S.
Gwo
,
Phys. Rev. Lett.
101
,
106803
(
2008
).
6.
H.
Lu
,
W. J.
Schaff
,
L. F.
Eastman
,
J.
Wu
,
W.
Walukiewicz
,
V.
Cimalla
, and
O.
Ambacher
,
Appl. Phys. Lett.
83
,
1136
(
2003
).
7.
P. D. C.
King
,
T. D.
Veal
,
C. F.
McConville
,
F.
Fuchs
,
J.
Furthmüller
,
F.
Bechstedt
,
P.
Schley
,
R.
Goldhahn
,
J.
Schörmann
,
D. J.
As
,
K.
Lischka
,
D.
Muto
,
H.
Naoi
,
Y.
Nanishi
,
H.
Lu
, and
W. J.
Schaff
,
Appl. Phys. Lett.
91
,
092101
(
2007
).
8.
E.
Calleja
,
J.
Grandal
,
M. A.
Sanchez-Garcia
,
M.
Niebelschütz
,
V.
Cimalla
, and
O.
Ambacher
,
Appl. Phys. Lett.
90
,
262110
(
2007
).
9.
G.
Koblmüller
,
G. D.
Metcalfe
,
M.
Wraback
,
F.
Wu
,
C. S.
Gallinat
, and
J. S.
Speck
,
Appl. Phys. Lett.
94
,
091905
(
2009
).
10.
G.
Koblmüller
,
C. S.
Gallinat
,
S.
Bernardis
,
J. S.
Speck
,
G. D.
Chern
,
E. D.
Readinger
,
H.
Shen
, and
M.
Wraback
,
Appl. Phys. Lett.
89
,
071902
(
2006
).
11.
P. D. C.
King
,
T. D.
Veal
,
H.
Lu
,
S. A.
Hatfield
,
W. J.
Schaff
, and
C. F.
McConville
,
Surf. Sci.
602
,
871
(
2008
).
12.
P. J.
Hansen
,
V.
Vaithyanathan
,
Y.
Wu
,
T.
Mates
,
S.
Heikman
,
U. K.
Mishra
,
R. A.
York
,
D. G.
Schlom
, and
J. S.
Speck
,
J. Vac. Sci. Technol. B
23
,
499
(
2005
).
13.
P. D. C.
King
,
T. D.
Veal
, and
C. F.
McConville
,
Phys. Rev. B
77
,
125305
(
2008
).
14.
S.
Doniach
and
M.
Šunjić
,
J. Phys. C
3
,
285
(
1970
).
15.
L. F. J.
Piper
,
T. D.
Veal
,
P. H.
Jefferson
,
C. F.
McConville
,
F.
Fuchs
,
J.
Furthmüller
,
F.
Bechstedt
,
H.
Lu
, and
W. J.
Schaff
,
Phys. Rev. B
72
,
245319
(
2005
).
16.
A.
Denisenko
,
C.
Pietzka
,
A.
Chuvilin
,
U.
Kaiser
,
H.
Lu
,
W. J.
Schaff
, and
E.
Kohn
,
J. Appl. Phys.
105
,
033702
(
2009
).
17.
D.
Segev
and
C. G.
Van de Walle
,
Surf. Sci.
601
,
L15
(
2007
).
18.
M.
McLaurin
and
J. S.
Speck
,
Phys. Status Solidi
1
,
110
(
2007
).
19.
P. P.
Paskov
,
R.
Schifano
,
B.
Monemar
,
T.
Paskova
,
S.
Figge
, and
D.
Hommel
,
J. Appl. Phys.
98
,
093519
(
2005
).
20.
C. S.
Gallinat
,
G.
Koblmüller
, and
J. S.
Speck
,
Appl. Phys. Lett.
95
,
022103
(
2009
).
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