InGaN-based multi-quantum well (MQW) solar cells are promising devices for photovoltaics (e.g., for tandem solar cells and concentrator systems), space applications, and wireless power transfer. In order to improve the efficiency of these devices, the factors limiting their efficiency and stability must be investigated in detail. Due to the complexity of a MQW structure, compared with a simple pn junction, modeling the spectral response of these solar cells is not straightforward, and ad hoc methodologies must be implemented. In this paper, we propose a model, based on material parameters and closed-formula equations, that describes the shape of the quantum efficiency of InGaN/GaN MQW solar cells, by taking into account the layer thickness, the temperature dependence of the absorption coefficient, and quantum confinement effects. We demonstrate (i) that the proposed model can effectively reproduce the spectral response of the cells; in addition, (ii) we prove that the bulk p-GaN layer absorbs radiation, but the carriers photogenerated in this region do not significantly contribute to device current. Finally, we show that (iii) by increasing the temperature, there is a redshift of the absorption edge due to bandgap narrowing, which can be described by Varshni law and is taken into account by the model, and a lowering in the extraction efficiency due to the increase in recombination (mostly Shockley–Read–Hall) inside the quantum wells, which is also visible by decreasing light intensity.

1.
See https://www.nrel.gov/pv/cell-efficiency.html for “NREL Research Cell Record Efficiency Chart;” accessed 10 January 2022.
2.
L. A.
Reichertz
,
I.
Gherasoiu
,
K. M.
Yu
,
V. M.
Kao
,
W.
Walukiewicz
, and
J. W.
Ager
, “
Demonstration of a III–nitride/silicon tandem solar cell
,”
Appl. Phys. Express
2
,
122202
(
2009
).
3.
N.
Laxmi
,
S.
Routray
, and
K. P.
Pradhan
, “
III–nitride/Si tandem solar cell for high spectral response: Key attributes of auto-tunneling mechanisms
,”
Silicon
12
,
2455
2463
(
2020
).
4.
G.
Moses
,
X.
Huang
,
Y.
Zhao
,
M.
Auf der Maur
,
E. A.
Katz
, and
J. M.
Gordon
, “
InGaN/GaN multi-quantum-well solar cells under high solar concentration and elevated temperatures for hybrid solar thermal-photovoltaic power plants
,”
Prog. Photovolt. Res. Appl.
28
,
1167
(
2020
).
5.
R.
Dahal
,
J.
Li
,
K.
Aryal
,
J. Y.
Lin
, and
H. X.
Jiang
, “
InGaN/GaN multiple quantum well concentrator solar cells
,”
Appl. Phys. Lett.
97
,
073115
(
2010
).
6.
X.
Zheng
,
D.
Zhang
,
X.
Li
,
Y.
Wu
,
H.
Wang
,
X.
Gan
,
N.
Wang
, and
H.
Yang
, “
InGaN-based multiple quantum well photovoltaic cells with good open-circuit voltage and concentration behavior
,” in
Proceedings of the 2013 IEEE 39th Photovoltaic Specialists Conference (PVSC)
(
IEEE
,
2013
), pp.
2154
2156
.
7.
D.-H.
Lien
,
Y.-H.
Hsiao
,
S.-G.
Yang
,
M.-L.
Tsai
,
T.-C.
Wei
,
S.-C.
Lee
, and
J.-H.
He
, “
Harsh photovoltaics using InGaN/GaN multiple quantum well schemes
,”
Nano Energy
11
,
104
109
(
2015
).
8.
C.
De Santi
,
M.
Meneghini
,
A.
Caria
,
E.
Dogmus
,
M.
Zegaoui
,
F.
Medjdoub
,
B.
Kalinic
,
T.
Cesca
,
G.
Meneghesso
, and
E.
Zanoni
, “
GaN-based laser wireless power transfer system
,”
Materials
11
,
153
(
2018
).
9.
Y.
Zhao
,
X.
Huang
,
H.
Fu
,
H.
Chen
,
Z.
Lu
,
J.
Montes
, and
I.
Baranowski
, “
InGaN-based solar cells for space applications
,” in
Midwest Symposium on Circuits and Systems
(
IEEE
,
2017
), pp.
954
957
.
10.
R.
Dahal
,
B.
Pantha
,
J.
Li
,
J. Y.
Lin
, and
H. X.
Jiang
, “
InGaN/GaN multiple quantum well solar cells with long operating wavelengths
,”
Appl. Phys. Lett.
94
,
063505
(
2009
).
11.
J.-K.
Sheu
,
F.-B.
Chen
,
S.-H.
Wu
,
M.-L.
Lee
,
P.-C.
Chen
, and
Y.-H.
Yeh
, “
Vertical InGaN-based green-band solar cells operating under high solar concentration up to 300 suns
,”
Opt. Express
22
,
A1222
(
2014
).
12.
X.
Huang
,
H.
Chen
,
H.
Fu
,
I.
Baranowski
,
J.
Montes
,
T. H.
Yang
,
K.
Fu
,
B. P.
Gunning
,
D. D.
Koleske
, and
Y.
Zhao
, “
Energy band engineering of InGaN/GaN multi-quantum-well solar cells via AlGaN electron- and hole-blocking layers
,”
Appl. Phys. Lett.
113
,
043501
(
2018
).
13.
A.
Caria
,
C.
De Santi
,
E.
Dogmus
,
F.
Medjdoub
,
E.
Zanoni
,
G.
Meneghesso
, and
M.
Meneghini
, “
Excitation intensity and temperature-dependent performance of InGaN/GaN multiple quantum wells photodetectors
,”
Electronics
9
,
1840
(
2020
).
14.
P. G.
Moses
and
C. G.
Van de Walle
, “
Band bowing and band alignment in InGaN alloys
,”
Appl. Phys. Lett.
96
,
021908
(
2010
).
15.
J. R.
Lang
,
N. G.
Young
,
R. M.
Farrell
,
Y.-R.
Wu
, and
J. S.
Speck
, “
Carrier escape mechanism dependence on barrier thickness and temperature in InGaN quantum well solar cells
,”
Appl. Phys. Lett.
101
,
181105
(
2012
).
16.
W.
Shockley
and
W. T.
Read
, “
Statistics of the recombinations of holes and electrons
,”
Phys. Rev.
87
,
835
842
(
1952
).
17.
M.
Meneghini
,
C.
De Santi
,
I.
Abid
,
M.
Buffolo
,
M.
Cioni
,
R. A.
Khadar
,
L.
Nela
,
N.
Zagni
,
A.
Chini
,
F.
Medjdoub
 et al., “
GaN-based power devices: Physics, reliability, and perspectives
,”
J. Appl. Phys.
130
,
181101
(
2021
).
18.
A.
Armstrong
,
A. R.
Arehart
,
B.
Moran
,
S. P.
DenBaars
,
U. K.
Mishra
,
J. S.
Speck
, and
S. A.
Ringel
, “
Impact of carbon on trap states in n-type GaN grown by metalorganic chemical vapor deposition
,”
Appl. Phys. Lett.
84
,
374
(
2004
).
19.
A. R.
Arehart
,
T.
Homan
,
M. H.
Wong
,
C.
Poblenz
,
J. S.
Speck
, and
S. A.
Ringel
, “
Impact of N- and Ga-face polarity on the incorporation of deep levels in n -type GaN grown by molecular beam epitaxy
,”
Appl. Phys. Lett.
96
,
242112
(
2010
).
20.
A. R.
Arehart
,
A.
Corrion
,
C.
Poblenz
,
J. S.
Speck
,
U. K.
Mishra
,
S. P.
DenBaars
, and
S. A.
Ringel
, “
Comparison of deep level incorporation in ammonia and rf-plasma assisted molecular beam epitaxy n-GaN films
,”
Phys. Status Solidi C
5
,
1750
1752
(
2008
).
21.
Y.
Nakano
, “
Deep-level defects in homoepitaxial p-type GaN
,”
J. Vac. Sci. Technol. A
36
,
023001
(
2018
).
22.
C. E.
Dreyer
,
A.
Alkauskas
,
J. L.
Lyons
,
J. S.
Speck
, and
C. G.
Van De Walle
, “
Gallium vacancy complexes as a cause of Shockley-Read-Hall recombination in III-nitride light emitters
,”
Appl. Phys. Lett.
108
,
141101
(
2016
).
23.
J. L.
Lyons
and
C. G.
Van De Walle
, “
Computationally predicted energies and properties of defects in GaN
,”
npj Comput. Mater.
3
,
1
10
(
2017
).
24.
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
).
25.
G. F.
Brown
,
J. W.
Ager
,
W.
Walukiewicz
, and
J.
Wu
, “
Finite element simulations of compositionally graded InGaN solar cells
,”
Sol. Energy Mater. Sol. Cells
94
,
478
483
(
2010
).
26.
M.
Fox
and
M.
Anthony
, Optical Properties of Solids (Oxford University Press, 2010), p. 396.
27.
F.
Urbach
, “
The long-wavelength edge of photographic sensitivity and of the electronic absorption of solids
,”
Phys. Rev.
92
,
1324
(
1953
).
28.
K. P.
O’Donnell
,
R. W.
Martin
, and
P. G.
Middleton
, “
Origin of luminescence from InGaN diodes
,”
Phys. Rev. Lett.
82
,
237
(
1999
).
29.
B.
Damilano
,
N.
Grandjean
,
J.
Massies
,
L.
Siozade
, and
J.
Leymarie
, “
InGaN/GaN quantum wells grown by molecular-beam epitaxy emitting from blue to red at 300 K
,”
Appl. Phys. Lett.
77
,
1268
(
2000
).
30.
C.
Wetzel
,
S.
Kamiyama
,
H.
Amano
, and
I.
Akasaki
, “
Optical absorption in polarized Ga1–xInxN/GaN quantum wells
,”
Jpn. J. Appl. Phys.
41
,
11
(
2002
).
31.
G.
Martin
,
A.
Botchkarev
,
A.
Rockett
, and
H.
Morkoç
, “
Valence-band discontinuities of wurtzite GaN, AlN, and InN heterojunctions measured by x-ray photoemission spectroscopy
,”
Appl. Phys. Lett.
68
,
2541
2543
(
1996
).
32.
U. M. E.
Christmas
,
A. D.
Andreev
, and
D. A.
Faux
, “
Calculation of electric field and optical transitions in InGaN∕GaN quantum wells
,”
J. Appl. Phys.
98
,
073522
(
2005
).
33.
A.
Gorai
,
S.
Panda
, and
D.
Biswas
, “
Advantages of InGaN/InGaN quantum well light emitting diodes: Better electron-hole overlap and stable output
,”
Optik
140
,
665
672
(
2017
).
34.
Z. Z.
Bandić
,
P. M.
Bridger
,
E. C.
Piquette
, and
T. C.
McGill
, “
Electron diffusion length and lifetime in p-type GaN
,”
Appl. Phys. Lett.
73
,
3276
(
1998
).
35.
X.
Zhang
,
D. H.
Rich
,
J. T.
Kobayashi
,
N. P.
Kobayashi
, and
P. D.
Dapkus
, “
Carrier relaxation and recombination in an InGaN/GaN quantum well probed with time-resolved cathodoluminescence
,”
Appl. Phys. Lett.
73
,
1430
(
1998
).
36.
Y.
Zhang
,
G.
Conibeer
,
S.
Liu
,
J.
Zhang
, and
J. F.
Guillemoles
, “
Review of the mechanisms for the phonon bottleneck effect in III–V semiconductors and their application for efficient hot carrier solar cells
,”
Prog. Photovolt. Res. Appl.
30
,
581
(
2022
).
37.
R.
Belghouthi
,
S.
Taamalli
,
F.
Echouchene
,
H.
Mejri
, and
H.
Belmabrouk
, “
Modeling of polarization charge in N-face InGaN/GaN MQW solar cells
,”
Mater. Sci. Semicond. Process.
40
,
424
428
(
2015
).
38.
S. C.
Jain
,
M.
Willander
,
J.
Narayan
, and
R. V.
Overstraeten
, “
III–nitrides growth, characterization, and properties
,”
J. Appl. Phys.
87
,
965
1006
(
2000
).
39.
J.
Wu
,
W.
Walukiewicz
,
K. M.
Yu
,
J. W.
Ager
 III
,
E. E.
Haller
,
H.
Lu
, and
W. J.
Schaff
, “
Small band gap bowing in In1−xGaxN alloys
,”
Appl. Phys. Lett.
80
,
4741
(
2002
).
40.
J.
Wu
and
W.
Walukiewicz
, “
Band gaps of InN and group III nitride alloys
,”
Superlattices Microstruct.
34
,
63
75
(
2003
).
41.
M. A.
Reshchikov
,
G.-C.
Yi
, and
B. W.
Wessels
, “
Behavior of 2.8- and 3.2-eV photoluminescence bands in Mg-doped GaN at different temperatures and excitation densities
,”
Phys. Rev. B
59
,
13176
(
1999
).
42.
M. A.
Reshchikov
and
H.
Morkoç
, “
Luminescence from defects in GaN
,”
Phys. B Condens. Matter
376–377
,
428
431
(
2006
).

Supplementary Material

You do not currently have access to this content.