The external quantum efficiency (EQE) and internal quantum efficiency (IQE) of radiation are quantified by omnidirectional photoluminescence measurements using an integrating sphere for two types of GaN crystals with different carbon concentrations ([C] =  1 × 10 14 cm 3 , 2 × 10 15 cm 3). In the sample with lower [C], when the excitation density is 140  W cm 2, the EQE and IQE for near-band-edge (NBE) emission are 0.787% and 21.7%, respectively. The relationship between [C] and the IQE for NBE emission indicates that carbon impurities work as effective nonradiative recombination centers (NRCs) in n-type GaN, and major NRCs switch from carbon impurities to intrinsic NRCs, such as vacancies, when [C] falls below 3.5 × 10 14 cm 3.

1.
Y.
Narukawa
,
M.
Ichikawa
,
D.
Sanga
,
M.
Sano
, and
T.
Mukai
, “
White light emitting diodes with super-high luminous efficacy
,”
J. Phys. D
43
,
354002
(
2010
).
2.
Y.
Saitoh
,
K.
Sumiyoshi
,
M.
Okada
,
T.
Horii
,
T.
Miyazaki
,
H.
Shiomi
,
M.
Ueno
,
K.
Katayama
,
M.
Kiyama
, and
T.
Nakamura
, “
Extremely low on-resistance and high breakdown voltage observed in vertical GaN schottky barrier diodes with high-mobility drift layers on low-dislocation-density GaN substrates
,”
Appl. Phys. Express
3
,
081001
(
2010
).
3.
J.
Kolník
,
c. H.
Oğuzman
,
K. F.
Brennan
,
R.
Wang
,
P. P.
Ruden
, and
Y.
Wang
, “
Electronic transport studies of bulk zincblende and wurtzite phases of GaN based on an ensemble Monte Carlo calculation including a full zone band structure
,”
J. Appl. Phys.
78
,
1033
1038
(
1995
).
4.
T.
Sugahara
,
H.
Sato
,
M.
Hao
,
Y.
Naoi
,
S.
Kurai
,
S.
Tottori
,
K.
Yamashita
,
K.
Nishino
,
L. T.
Romano
, and
S.
Sakai
, “
Direct evidence that dislocations are non-radiative recombination centers in GaN
,”
Jpn. J. Appl. Phys., Part 2
37
,
L398
(
1998
).
5.
K.
Motoki
,
T.
Okahisa
,
S.
Nakahata
,
N.
Matsumoto
,
H.
Kimura
,
H.
Kasai
,
K.
Takemoto
,
K.
Uematsu
,
M.
Ueno
,
Y.
Kumagai
,
A.
Koukitu
, and
H.
Seki
, “
Growth and characterization of freestanding GaN substrates
,”
J. Cryst. Growth
237
,
912
921
(
2002
).
6.
Y.
Oshima
,
T.
Eri
,
M.
Shibata
,
H.
Sunakawa
,
K.
Kobayashi
,
T.
Ichihashi
, and
A.
Usui
, “
Preparation of freestanding GaN wafers by hydride vapor phase epitaxy with void-assisted separation
,”
Jpn. J. Appl. Phys., Part 2
42
,
L1
(
2003
).
7.
M.
Saito
,
D. S.
Kamber
,
T. J.
Baker
,
K.
Fujito
,
S. P.
DenBaars
,
J. S.
Speck
, and
S.
Nakamura
, “
Plane dependent growth of GaN in supercritical basic ammonia
,”
Appl. Phys. Express
1
,
121103
(
2008
).
8.
K.
Fujito
,
S.
Kubo
,
H.
Nagaoka
,
T.
Mochizuki
,
H.
Namita
, and
S.
Nagao
, “
Bulk GaN crystals grown by HVPE
,”
J. Cryst. Growth
311
,
3011
3014
(
2009
).
9.
R.
Dwiliński
,
R.
Doradziński
,
J.
Garczyński
,
L.
Sierzputowski
,
R.
Kucharski
,
M.
Zając
,
M.
Rudziński
,
R.
Kudrawiec
,
W.
Strupiński
, and
J.
Misiewicz
, “
Ammonothermal GaN substrates: Growth accomplishments and applications
,”
Phys. Status Solidi A
208
,
1489
1493
(
2011
).
10.
T.
Yoshida
,
Y.
Oshima
,
K.
Watanabe
,
T.
Tsuchiya
, and
T.
Mishima
, “
Ultrahigh-speed growth of GaN by hydride vapor phase epitaxy
,”
Phys. Status Solidi C
8
,
2110
2112
(
2011
).
11.
Q.
Bao
,
M.
Saito
,
K.
Hazu
,
K.
Furusawa
,
Y.
Kagamitani
,
R.
Kayano
,
D.
Tomida
,
K.
Qiao
,
T.
Ishiguro
,
Y.
Chiaki
, and
S.
Chichibu
, “
Ammonothermal crystal growth of GaN using an NH4F mineralizer
,”
Cryst. Growth Des.
13
,
4158
(
2013
).
12.
Y.
Mori
,
M.
Imade
,
M.
Maruyama
, and
M.
Yoshimura
, “
Growth of GaN crystals by Na flux method
,”
ECS J. Solid State Sci. Technol.
2
,
N3068
(
2013
).
13.
Y.
Mikawa
,
T.
Ishinabe
,
S.
Kawabata
,
T.
Mochizuki
,
A.
Kojima
,
Y.
Kagamitani
, and
H.
Fujisawa
,
Ammonothermal Growth of Polar and Non-Polar Bulk GaN Crystal
(
SPIE
,
2015
), p.
936302
.
14.
Y.
Tsukada
,
Y.
Enatsu
,
S.
Kubo
,
H.
Ikeda
,
K.
Kurihara
,
H.
Matsumoto
,
S.
Nagao
,
Y.
Mikawa
, and
K.
Fujito
, “
High-quality, 2-inch-diameter m-plane GaN substrates grown by hydride vapor phase epitaxy on acidic ammonothermal seeds
,”
Jpn. J. Appl. Phys., Part 1
55
,
05FC01
(
2016
).
15.
S.
Pimputkar
,
J.
Speck
, and
S.
Nakamura
, “
Basic ammonothermal GaN growth in molybdenum capsules
,”
J. Cryst. Growth
456
,
15
20
(
2016
).
16.
G.
Piao
,
K.
Ikenaga
,
Y.
Yano
,
H.
Tokunaga
,
A.
Mishima
,
Y.
Ban
,
T.
Tabuchi
, and
K.
Matsumoto
, “
Study of carbon concentration in GaN grown by metalorganic chemical vapor deposition
,”
J. Cryst. Growth
456
,
137
139
(
2016
).
17.
Z. Z.
Bandić
,
P. M.
Bridger
,
E. C.
Piquette
, and
T. C.
McGill
, “
Minority carrier diffusion length and lifetime in GaN
,”
Appl. Phys. Lett.
72
,
3166
3168
(
1998
).
18.
K. C.
Collins
,
A. M.
Armstrong
,
A. A.
Allerman
,
G.
Vizkelethy
,
S. B.
Van Deusen
,
F.
Léonard
, and
A. A.
Talin
, “
Proton irradiation effects on minority carrier diffusion length and defect introduction in homoepitaxial and heteroepitaxial n-GaN
,”
J. Appl. Phys.
122
,
235705
(
2017
).
19.
J.
Wang
,
X.
Wang
,
J.
Chen
,
X.
Gao
,
X.
Zeng
,
H.
Mao
, and
K.
Xu
, “
Investigation on minority carrier lifetime, diffusion length and recombination mechanism of Mg-doped GaN grown by MOCVD
,”
J. Alloys Compd.
870
,
159477
(
2021
).
20.
F.
Horikiri
,
Y.
Narita
,
T.
Yoshida
,
T.
Kitamura
,
H.
Ohta
,
T.
Nakamura
, and
T.
Mishima
, “
Wafer-level nondestructive inspection of substrate off-angle and net donor concentration of the n-drift layer in vertical GaN-on-GaN schottky diodes
,”
Jpn. J. Appl. Phys., Part 1
56
,
061001
(
2017
).
21.
L.
Jiang
,
J.
Liu
,
A.
Tian
,
X.
Ren
,
S.
Huang
,
W.
Zhou
,
L.
Zhang
,
D.
Li
,
S.
Zhang
,
M.
Ikeda
et al, “
Influence of substrate misorientation on carbon impurity incorporation and electrical properties of p-GaN grown by metalorganic chemical vapor deposition
,”
Appl. Phys. Express
12
,
055503
(
2019
).
22.
J. L.
Lyons
,
A.
Janotti
, and
C. G.
Van de Walle
, “
Effects of carbon on the electrical and optical properties of InN, GaN, and AlN
,”
Phys. Rev. B
89
,
035204
(
2014
).
23.
M.
Matsubara
and
E.
Bellotti
, “
A first-principles study of carbon-related energy levels in GaN. I. Complexes formed by substitutional/interstitial carbons and gallium/nitrogen vacancies
,”
J. Appl. Phys.
121
,
195701
(
2017
).
24.
S. G.
Christenson
,
W.
Xie
,
Y. Y.
Sun
, and
S. B.
Zhang
, “
Carbon as a source for yellow luminescence in GaN: Isolated CN defect or its complexes
,”
J. Appl. Phys.
118
,
135708
(
2015
).
25.
J. L.
Lyons
,
A.
Janotti
, and
C. G.
Van de Walle
, “
Carbon impurities and the yellow luminescence in GaN
,”
Appl. Phys. Lett.
97
,
152108
(
2010
).
26.
T.
Ogino
and
M.
Aoki
, “
Mechanism of yellow luminescence in GaN
,”
Jpn. J. Appl. Phys., Part 1
19
,
2395
(
1980
).
27.
H.
Tang
,
J. B.
Webb
,
J. A.
Bardwell
,
S.
Raymond
,
J.
Salzman
, and
C.
Uzan-Saguy
, “
Properties of carbon-doped GaN
,”
Appl. Phys. Lett.
78
,
757
759
(
2001
).
28.
C. H.
Seager
,
A. F.
Wright
,
J.
Yu
, and
W.
Götz
, “
Role of carbon in GaN
,”
J. Appl. Phys.
92
,
6553
6560
(
2002
).
29.
R.
Armitage
,
W.
Hong
,
Q.
Yang
,
H.
Feick
,
J.
Gebauer
,
E. R.
Weber
,
S.
Hautakangas
, and
K.
Saarinen
, “
Contributions from gallium vacancies and carbon-related defects to the ‘yellow luminescence’ in GaN
,”
Appl. Phys. Lett.
82
,
3457
3459
(
2003
).
30.
R.
Armitage
,
Q.
Yang
, and
E. R.
Weber
, “
Analysis of the carbon-related ‘blue’ luminescence in GaN
,”
J. Appl. Phys.
97
,
073524
(
2005
).
31.
M. A.
Reshchikov
and
H.
Morkoç
, “
Luminescence properties of defects in GaN
,”
J. Appl. Phys.
97
,
061301
(
2005
).
32.
M. A.
Reshchikov
,
D. O.
Demchenko
,
J. D.
McNamara
,
S.
Fernández-Garrido
, and
R.
Calarco
, “
Green luminescence in Mg-doped GaN
,”
Phys. Rev. B
90
,
035207
(
2014
).
33.
M. A.
Reshchikov
,
M.
Vorobiov
,
D. O.
Demchenko
,
U.
Özgür
,
H.
Morkoç
,
A.
Lesnik
,
M. P.
Hoffmann
,
F.
Hörich
,
A.
Dadgar
, and
A.
Strittmatter
, “
Two charge states of the CN acceptor in GaN: Evidence from photoluminescence
,”
Phys. Rev. B
98
,
125207
(
2018
).
34.
M. A.
Reshchikov
,
J. D.
McNamara
,
H.
Helava
,
A.
Usikov
, and
Y.
Makarov
, “
Two yellow luminescence bands in undoped GaN
,”
Sci. Rep.
8
,
8091
(
2018
).
35.
K.
Kojima
,
F.
Horikiri
,
Y.
Narita
,
T.
Yoshida
,
H.
Fujikura
, and
S. F.
Chichibu
, “
Roles of carbon impurities and intrinsic nonradiative recombination centers on the carrier recombination processes of GaN crystals
,”
Appl. Phys. Express
13
,
012004
(
2019
).
36.
D. V.
Lang
, “
Deep-level transient spectroscopy: A new method to characterize traps in semiconductors
,”
J. Appl. Phys.
45
,
3023
3032
(
1974
).
37.
D.
Haase
,
M.
Schmid
,
W.
Kürner
,
A.
Dörnen
,
V.
Härle
,
F.
Scholz
,
M.
Burkard
, and
H.
Schweizer
, “
Deep-level defects and n-type-carrier concentration in nitrogen implanted GaN
,”
Appl. Phys. Lett.
69
,
2525
2527
(
1996
).
38.
A.
Armstrong
,
A. R.
Arehart
,
D.
Green
,
U. K.
Mishra
,
J. S.
Speck
, and
S. A.
Ringel
, “
Impact of deep levels on the electrical conductivity and luminescence of gallium nitride codoped with carbon and silicon
,”
J. Appl. Phys.
98
,
053704
(
2005
).
39.
U.
Honda
,
Y.
Yamada
,
Y.
Tokuda
, and
K.
Shiojima
, “
Deep levels in n-GaN doped with carbon studied by deep level and minority carrier transient spectroscopies
,”
Jpn. J. Appl. Phys., Part 1
51
,
04DF04
(
2012
).
40.
T.
Tanaka
,
K.
Shiojima
,
T.
Mishima
, and
Y.
Tokuda
, “
Deep-level transient spectroscopy of low-free-carrier-concentration n-GaN layers grown on freestanding GaN substrates: Dependence on carbon compensation ratio
,”
Jpn. J. Appl. Phys., Part 1
55
,
061101
(
2016
).
41.
H.
Yamada
,
H.
Chonan
,
T.
Takahashi
,
T.
Yamada
, and
M.
Shimizu
, “
Deep-level traps in lightly Si-doped n-GaN on free-standing m-oriented GaN substrates
,”
AIP Adv.
8
,
045311
(
2018
).
42.
K.
Kanegae
,
H.
Fujikura
,
Y.
Otoki
,
T.
Konno
,
T.
Yoshida
,
M.
Horita
,
T.
Kimoto
, and
J.
Suda
, “
Deep-level transient spectroscopy studies of electron and hole traps in n-type GaN homoepitaxial layers grown by quartz-free hydride-vapor-phase epitaxy
,”
Appl. Phys. Lett.
115
,
012103
(
2019
).
43.
G.
Alfieri
and
V. K.
Sundaramoorthy
, “
Defect energy levels in carbon implanted n-type homoepitaxial GaN
,”
J. Appl. Phys.
126
,
125301
(
2019
).
44.
T.
Narita
,
M.
Horita
,
K.
Tomita
,
T.
Kachi
, and
J.
Suda
, “
Why do electron traps at EC −0.6 eV have inverse correlation with carbon concentrations in n-type GaN layers?
,”
Jpn. J. Appl. Phys., Part 1
59
,
105505
(
2020
).
45.
Y.
Zhang
,
Z.
Chen
,
W.
Li
,
H.
Lee
,
M. R.
Karim
,
A. R.
Arehart
,
S. A.
Ringel
,
S.
Rajan
, and
H.
Zhao
, “
Probing unintentional Fe impurity incorporation in MOCVD homoepitaxy GaN: Toward GaN vertical power devices
,”
J. Appl. Phys.
127
,
215707
(
2020
).
46.
F.
Kaess
,
S.
Mita
,
J.
Xie
,
P.
Reddy
,
A.
Klump
,
L. H.
Hernandez-Balderrama
,
S.
Washiyama
,
A.
Franke
,
R.
Kirste
,
A.
Hoffmann
,
R.
Collazo
, and
Z.
Sitar
, “
Correlation between mobility collapse and carbon impurities in Si-doped GaN grown by low pressure metalorganic chemical vapor deposition
,”
J. Appl. Phys.
120
,
105701
(
2016
).
47.
T.
Kimura
,
T.
Konno
, and
H.
Fujikura
, “
Substantial and simultaneous reduction of major electron traps and residual carbon in homoepitaxial GaN layers
,”
Appl. Phys. Lett.
118
,
182104
(
2021
).
48.
A.
Ishitani
,
K.
Okuno
,
A.
Karen
,
S.
Karen
, and
F.
Soeda
, in
Proceedings of International Conference on Materials and Process Characterization for VLSI
,
1988
.
49.
M.
Sumiya
,
K.
Yoshimura
,
K.
Ohtsuka
, and
S.
Fuke
, “
Dependence of impurity incorporation on the polar direction of GaN film growth
,”
Appl. Phys. Lett.
76
,
2098
2100
(
2000
).
50.
N.
Fichtenbaum
,
T.
Mates
,
S.
Keller
,
S.
DenBaars
, and
U.
Mishra
, “
Impurity incorporation in heteroepitaxial n-face and Ga-face GaN films grown by metalorganic chemical vapor deposition
,”
J. Cryst. Growth
310
,
1124
1131
(
2008
).
51.
K.
Kojima
,
T.
Ohtomo
,
K.
Ikemura
,
Y.
Yamazaki
,
M.
Saito
,
H.
Ikeda
,
K.
Fujito
, and
S. F.
Chichibu
, “
Determination of absolute value of quantum efficiency of radiation in high quality GaN single crystals using an integrating sphere
,”
J. Appl. Phys.
120
,
015704
(
2016
).
52.
D.
Wickramaratne
,
J.-X.
Shen
,
C. E.
Dreyer
,
M.
Engel
,
M.
Marsman
,
G.
Kresse
,
S.
Marcinkevičius
,
A.
Alkauskas
, and
C. G.
Van de Walle
, “
Iron as a source of efficient Shockley-Read-Hall recombination in GaN
,”
Appl. Phys. Lett.
109
,
162107
(
2016
).
53.
K.
Kojima
,
H.
Ikeda
,
K.
Fujito
, and
S. F.
Chichibu
, “
Demonstration of omnidirectional photoluminescence (ODPL) spectroscopy for precise determination of internal quantum efficiency of radiation in GaN single crystals
,”
Appl. Phys. Lett.
111
,
032111
(
2017
).
54.
M. A.
Reshchikov
,
D. O.
Demchenko
,
A.
Usikov
,
H.
Helava
, and
Y.
Makarov
, “
Carbon defects as sources of the green and yellow luminescence bands in undoped GaN
,”
Phys. Rev. B
90
,
235203
(
2014
).
55.
W. P.
Dumke
, “
Spontaneous radiative recombination in semiconductors
,”
Phys. Rev.
105
,
139
144
(
1957
).
56.
P.
Asbeck
, “
Self-absorption effects on the radiative lifetime in GaAs-GaAlAs double heterostructures
,”
J. Appl. Phys.
48
,
820
822
(
1977
).
57.
J.
Neugebauer
and
C. G.
Van de Walle
, “
Gallium vacancies and the yellow luminescence in GaN
,”
Appl. Phys. Lett.
69
,
503
505
(
1996
).
58.
K.
Saarinen
,
T.
Laine
,
S.
Kuisma
,
J.
Nissilä
,
P.
Hautojärvi
,
L.
Dobrzynski
,
J. M.
Baranowski
,
K.
Pakula
,
R.
Stepniewski
,
M.
Wojdak
,
A.
Wysmolek
,
T.
Suski
,
M.
Leszczynski
,
I.
Grzegory
, and
S.
Porowski
, “
Observation of native Ga vacancies in GaN by positron annihilation
,”
Phys. Rev. Lett.
79
,
3030
3033
(
1997
).
59.
K.
Kojima
and
S. F.
Chichibu
, “
Urbach-martienssen tail as the origin of the two-peak structure in the photoluminescence spectra for the near-band-edge emission of a freestanding GaN crystal observed by omnidirectional photoluminescence spectroscopy
,”
Appl. Phys. Lett.
117
,
171103
(
2020
).
60.
K.
Kojima
,
K.
Ikemura
,
K.
Matsumori
,
Y.
Yamada
,
Y.
Kanemitsu
, and
S. F.
Chichibu
, “
Internal quantum efficiency of radiation in a bulk CH3NH3PbBr3 perovskite crystal quantified by using the omnidirectional photoluminescence spectroscopy
,”
APL Mater.
7
,
071116
(
2019
).
61.
K.
Kojima
and
S. F.
Chichibu
, “
Correlation between the internal quantum efficiency and photoluminescence lifetime of the near-band-edge emission in a ZnO single crystal grown by the hydrothermal method
,”
Appl. Phys. Express
13
,
121005
(
2020
).
62.
S. F.
Chichibu
,
A.
Uedono
,
K.
Kojima
,
H.
Ikeda
,
K.
Fujito
,
S.
Takashima
,
M.
Edo
,
K.
Ueno
, and
S.
Ishibashi
, “
The origins and properties of intrinsic nonradiative recombination centers in wide bandgap GaN and AlGaN
,”
J. Appl. Phys.
123
,
161413
(
2018
).
63.
S. F.
Chichibu
,
K.
Hazu
,
Y.
Ishikawa
,
M.
Tashiro
,
H.
Namita
,
S.
Nagao
,
K.
Fujito
, and
A.
Uedono
, “
Time-resolved photoluminescence, positron annihilation, and Al0.23Ga0.77N/GaN heterostructure growth studies on low defect density polar and nonpolar freestanding GaN substrates grown by hydride vapor phase epitaxy
,”
J. Appl. Phys.
111
,
103518
(
2012
).
64.
K.
Kawakami
,
T.
Nakano
, and
A. A.
Yamaguchi
,
Proc. SPIE
9748
,
97480S
(
2016
).
65.
S.
Ichikawa
,
Y.
Matsuda
,
H.
Dojo
,
M.
Funato
,
Y.
Kawakami
, and
K.
Kojima
, in
The 14th International Conference on Nitride Semiconductors
,
2023
.
You do not currently have access to this content.