In amorphous/crystalline silicon heterojunction solar cells, optical losses can be mitigated by replacing the amorphous silicon films by wider bandgap amorphous silicon oxide layers. In this article, we use stacks of intrinsic amorphous silicon and amorphous silicon oxide as front intrinsic buffer layers and show that this increases the short-circuit current density by up to 0.43 mA/cm2 due to less reflection and a higher transparency at short wavelengths. Additionally, high open-circuit voltages can be maintained, thanks to good interface passivation. However, we find that the gain in current is more than offset by losses in fill factor. Aided by device simulations, we link these losses to impeded carrier collection fundamentally caused by the increased valence band offset at the amorphous/crystalline interface. Despite this, carrier extraction can be improved by raising the temperature; we find that cells with amorphous silicon oxide window layers show an even lower temperature coefficient than reference heterojunction solar cells (−0.1%/°C relative drop in efficiency, compared to −0.3%/°C). Hence, even though cells with oxide layers do not outperform cells with the standard design at room temperature, at higher temperatures—which are closer to the real working conditions encountered in the field—they show superior performance in both experiment and simulation.

1.
S.
De Wolf
,
A.
Descoeudres
,
Z. C.
Holman
, and
C.
Ballif
,
Green
2
,
7
(
2012
).
2.
D. L.
Bätzner
,
Y.
Andrault
,
L.
Andreetta
,
A.
Büchel
,
W.
Frammelsberger
,
C.
Guérin
,
N.
Holm
,
D.
Lachenal
,
J.
Meixenberger
,
P.
Papet
,
B.
Rau
,
B.
Strahm
,
G.
Wahli
, and
F.
Wünsch
, in
26th European Photovoltaic Solar Energy Conference and Exhibition
(
Hamburg
,
Germany
,
2011
), p.
1073
.
3.
A.
Descoeudres
,
L.
Barraud
,
S.
De Wolf
,
B.
Strahm
,
D.
Lachenal
,
C.
Guérin
,
Z. C.
Holman
,
F.
Zicarelli
,
B.
Demaurex
,
J. P.
Seif
,
J.
Holovsky
, and
C.
Ballif
,
Appl. Phys. Lett.
99
,
123506
(
2011
).
4.
J. L.
Hernandez
,
K.
Yoshikawa
,
A.
Feltrin
,
N.
Menou
,
N.
Valckx
,
E.
Van Assche
,
J.
Poortmans
,
D.
Adachi
,
M.
Yoshimi
,
T.
Uto
,
H.
Uzo
,
T.
Kuchiyama
,
C.
Allebe
,
N.
Nakanishi
,
T.
Terashita
,
T.
Fujimoto
,
G.
Koizumi
, and
K.
Yamamoto
, in
21st International Photovoltaic Science and Engineering Conference
(
Fukuoka
,
Japan
,
2011
).
5.
T.
Kinoshita
,
D.
Fujishima
,
A.
Yano
,
A.
Ogane
,
S.
Tohoda
,
K.
Matsuyama
,
Y.
Nakamura
,
N.
Tokuoka
,
H.
Kanno
,
H.
Sakata
,
M.
Taguchi
, and
E.
Maruyama
, in
26th European Photovoltaic Solar Energy Conference and Exhibition
(
Hamburg
,
Germany
,
2011
), p.
871
.
6.
7.
P.
Würfel
,
Physics of Solar Cells
(
Wiley-VCH
,
2008
).
8.
J.-H.
Choi
,
S.-K.
Kim
,
J.-C.
Lee
,
H.
Park
,
W.-J.
Lee
, and
E.-C.
Cho
, in
26th European Photovoltaic Solar Energy Conference and Exhibition
(
Hamburg
,
Germany
,
2011
), p.
3302
.
9.
A.
Descoeudres
,
Z. C.
Holman
,
L.
Barraud
,
S.
Morel
,
S.
De Wolf
, and
C.
Ballif
,
IEEE J. Photovolt.
3
,
83
(
2013
).
10.
S.
Martín de Nicolás
,
D.
Muñoz
,
A. S.
Ozanne
,
N.
Nguyen
, and
P. J.
Ribeyron
,
Energy Procedia
8
,
226
(
2011
).
11.
M.
Tanaka
,
M.
Taguchi
,
T.
Matsuyama
,
T.
Sawada
,
S.
Tsuda
,
S.
Nakano
,
H.
Hanafusa
, and
Y.
Kuwano
,
Jpn. J. Appl. Phys., Part 1
31
,
3518
(
1992
).
12.
H.
Fujiwara
and
M.
Kondo
,
J. Appl. Phys.
101
,
054516
(
2007
).
13.
N.
Jensen
,
R. M.
Hausner
,
R. B.
Bergmann
,
J. H.
Werner
, and
U.
Rau
,
Prog. Photovoltaics Res. Appl.
10
,
1
(
2002
).
14.
D.
Pysch
,
C.
Meinhard
,
N.-P.
Harder
,
M.
Hermle
, and
S. W.
Glunz
,
J. Appl. Phys.
110
,
094516
(
2011
).
15.
Z. C.
Holman
,
A.
Descoeudres
,
L.
Barraud
,
F.
Zicarelli Fernandez
,
J. P.
Seif
,
S.
De Wolf
, and
C.
Ballif
,
IEEE J. Photovolt.
2
,
7
(
2012
).
16.
P.
Cuony
,
M.
Marending
,
D. T. L.
Alexander
,
M.
Boccard
,
G.
Bugnon
,
M.
Despeisse
, and
C.
Ballif
,
Appl. Phys. Lett.
97
,
213502
(
2010
).
17.
A.
Lambertz
,
T.
Grundler
, and
F.
Finger
,
J. Appl. Phys.
109
,
113109
(
2011
).
18.
K.
Ding
,
U.
Aeberhard
,
F.
Finger
, and
U.
Rau
,
Phys. Status Solidi (RRL)
6
,
193
(
2012
).
19.
K.
Ding
,
U.
Aeberhard
,
F.
Finger
, and
U.
Rau
,
J. Appl. Phys.
113
,
134501
(
2013
).
20.
F.
Einsele
,
W.
Beyer
, and
U.
Rau
,
J. Appl. Phys.
112
,
054905
(
2012
).
21.
T.
Mueller
,
S.
Schwertheim
, and
W. R.
Fahrner
,
J. Appl. Phys.
107
,
014504
(
2010
).
22.
A.
Janotta
,
R.
Janssen
,
M.
Schmidt
,
T.
Graf
,
M.
Stutzmann
,
L.
Görgens
,
A.
Bergmaier
,
G.
Dollinger
,
C.
Hammerl
,
S.
Schreiber
, and
B.
Stritzker
,
Phys. Rev. B
69
,
115206
(
2004
).
23.
R. A.
Sinton
and
A.
Cuevas
,
Appl. Phys. Lett.
69
,
2510
(
1996
).
24.
B.
Demaurex
,
S.
De Wolf
,
A.
Descoeudres
,
Z. C.
Holman
, and
C.
Ballif
,
Appl. Phys. Lett.
101
,
171604
(
2012
).
25.
F.
Zicarelli
,
A.
Descoeudres
,
G.
Choong
,
P.
Bôle
,
L.
Barraud
,
S.
De Wolf
, and
C.
Ballif
, in
25th European Photovoltaic Solar Energy Conference and Exhibition
(
Valencia
,
Spain
,
2010
), p.
1669
.
26.
R. A.
Sinton
and
A.
Cuevas
, in
16th European Photovoltaic Solar Energy Conference
(
Glasgow
,
UK
,
2000
), p.
1
.
27.
S.
De Wolf
and
M.
Kondo
,
Appl. Phys. Lett.
91
,
112109
(
2007
).
28.
L.-N.
He
,
D.-M.
Wang
, and
S.
Hasegawa
,
J. Non-Cryst. Solids
261
,
67
(
2000
).
29.
D.
Jousse
,
E.
Bustarret
, and
F.
Boulitrop
,
Solid State Commun.
55
,
435
(
1985
).
30.
S.
De Wolf
,
S.
Olibet
, and
C.
Ballif
,
Appl. Phys. Lett.
93
,
032101
(
2008
).
32.
P.
Gupta
,
V. L.
Colvin
, and
S. M.
George
,
Phys. Rev. B
37
,
8234
(
1988
).
33.
M.
Cardona
,
Phys. Status Solidi B
118
,
463
(
1983
).
34.
H.
Wagner
and
W.
Beyer
,
Solid State Commun.
48
,
585
(
1983
).
35.
T. F.
Schulze
,
H. N.
Beushausen
,
C.
Leendertz
,
A.
Dobrich
,
B.
Rech
, and
L.
Korte
,
Appl. Phys. Lett.
96
,
252102
(
2010
).
36.
L.
Zhao
,
H.
Diao
,
X.
Zeng
,
C.
Zhou
,
H.
Li
, and
W.
Wang
,
Physica B
405
,
61
(
2010
).
37.
J. C.
Knights
,
R. A.
Street
, and
G.
Lucovsky
,
J. Non-Cryst. Solids
35 & 36
,
279
(
1980
).
38.
P.
Cuony
,
D. T. L.
Alexander
,
I.
Perez-Wurfl
,
M.
Despeisse
,
G.
Bugnon
,
M.
Boccard
,
T.
Soderstrom
,
A.
Hessler-Wyser
,
C.
Hebert
, and
C.
Ballif
,
Adv. Mater.
24
,
1182
(
2012
).
39.
S. M.
Iftiquar
,
J. Phys. D: Appl. Phys.
31
,
1630
(
1998
).
40.
S.
Kageyama
,
M.
Akagawa
, and
H.
Fujiwara
,
Phys. Rev. B
83
,
195205
(
2011
).
41.
T. F.
Schulze
,
L.
Korte
,
F.
Ruske
, and
B.
Rech
,
Phys. Rev. B
83
,
165314
(
2011
).
42.
A. H. M.
Smets
,
M. A.
Wank
,
B.
Vet
,
M.
Fischer
,
R. A. C. M. M.
van Swaaij
,
M.
Zeman
,
D. C.
Bobela
,
C. R.
Wronski
, and
R. M. C. M.
van de Sanden
,
IEEE J. Photovolt.
2
,
94
(
2012
).
43.
J.
Geissbuühler
,
S.
De Wolf
,
B.
Demaurex
,
J. P.
Seif
,
D. T. L.
Alexander
,
L.
Barraud
, and
C.
Ballif
,
Appl. Phys. Lett.
102
,
231604
(
2013
).
44.
M.
Niwano
,
J.-i.
Kageyama
,
K.
Kinashi
,
N.
Miyamoto
, and
K.
Honma
,
J. Vac. Sci. Technol., A
12
,
465
(
1994
).
45.
A.
Bacioğlu
,
A. O.
Kodolbaş
, and
Ö.
Öktü
,
Sol. Energy Mater. Sol. Cells
89
,
49
(
2005
).
46.
S. C.
Baker-Finch
and
K. R.
McIntosh
, in
35th IEEE Photovoltaic Specialists Conference
(
Honolulu
,
HI, USA
,
2010
), p.
002184
.
47.
The deviation from the predicted value of 0.81 mA/cm2, for both J-V and EQE measurements can be explained by a spectral mismatch of the three different spectra used for simulation and the two measurements.
48.
T.
Tiedje
,
E.
Yablonovitch
,
G. D.
Cody
, and
B. G.
Brooks
,
IEEE Trans. Electron Devices
ED-31
,
711
(
1984
).
49.
Z.
Shu
,
U.
Das
,
J.
Allen
,
R.
Birkmire
, and
S.
Hegedus
,
Prog. Photovoltaics
(
2013
).
50.
M. W. M.
Van Cleef
,
F. A.
Rubinelli
,
R.
Rizzoli
, and
R.
Pinghini
,
Jpn. J. Appl. Phys., Part 1
37
,
3926
(
1998
).
51.
M.
Rahmouni
,
A.
Datta
,
P.
Chatterjee
,
J.
Damon-Lacoste
,
C.
Ballif
, and
P.
Roca i Cabarrocas
,
J. Appl. Phys.
107
,
054521
(
2010
).
52.
D. A.
Clugston
and
P. A.
Basore
, in
26th IEEE Photovoltaic Specialists Conference
(
Anaheim
,
CA, USA
,
1997
), p.
207
.
53.
J.
Krč
,
F.
Smole
, and
M.
Topič
,
Prog. Photovoltaics Res. Appl.
11
,
15
(
2003
).
54.
M.
Nerat
,
G.
Cernivec
,
F.
Smole
, and
M.
Topič
, in
24th European Photovoltaic Solar Energy Conference
(
Hamburg
,
Germany
,
2009
), p.
2433
.
55.
Z. C.
Holman
,
M.
Filipič
,
A.
Descoeudres
,
S.
De Wolf
,
F.
Smole
,
M.
Topič
, and
C.
Ballif
,
J. Appl. Phys.
113
,
013107
(
2013
).
56.
M.
Lu
,
U.
Das
,
S.
Bowden
,
S.
Hegedus
, and
R.
Birkmire
,
Prog. Photovoltaics Res. Appl.
19
,
326
(
2011
).
57.
M.
Filipič
,
Z. C.
Holman
,
F.
Smole
,
S.
De Wolf
,
C.
Ballif
, and
M.
Topič
,
J. Appl. Phys.
114
,
074504
(
2013
).
58.
R. L.
Anderson
,
Appl. Phys. Lett.
27
,
691
(
1975
).
59.
M.
Taguchi
,
E.
Maruyama
, and
M.
Tanaka
,
Jpn. J. Appl. Phys., Part 1
47
,
814
(
2008
).
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