All transparent high-performance solar-blind n-ITO/p-NiO/n-ZnO ultraviolet heterojunction bipolar phototransistors (HBPTs) were fabricated using a low-cost radio frequency magnetron sputtering system. In the HBPT structure, ITO, NiO, and ZnO were employed as the emitter, base, and collector, respectively. The applied voltage is across the emitter and collector, and the base is floating. The photocurrent increases with the collector–emitter voltage (VCE). The prepared HBPTs presented the highest optical gain of 7.4 × 104 and a responsivity of 1.67 × 104 A/W, at VCE = 4 V for the 280-nm illumination wavelength. As VCE exceeds 4 V, the optical gain and responsivity decrease owing to the punch-through effect. The prepared HBPTs have an ultraviolet (UV)/visible rejection ratio of more than three orders, allowing their use in practical applications as UV detectors for weak UV signals.

1.
Z.
Chen
,
B.
Li
,
X.
MO
,
S.
Li
,
J.
Wen
,
H.
Lei
,
Z.
Zhu
,
G.
Yang
,
P.
Gui
,
F.
Yao
, and
G.
Fang
, “
Self-powered narrowband p-NiO/n-ZnO nanowire ultraviolet photodetector with interface modification of Al2O3
,”
Appl. Phys. Lett.
110
,
123504
(
2017
).
2.
C. L.
Hsu
,
Y. C.
Wang
,
S. P.
Chang
, and
S. J.
Chang
, “
Ultraviolet/visible photodetectors based on p–n NiO/ZnO nanowires decorated with Pd nanoparticles
,”
ACS Appl. Nano Mater.
2
,
6343
6351
(
2019
).
3.
J. D.
Hwang
and
W. M.
Lin
, “
Enhancing the photoresponse of p-NiO/n-ZnO heterojunction photodiodes using post ZnO treatment
,”
IEEE Trans. Nanotechnol.
18
,
126
131
(
2019
).
4.
A.
Echresh
,
C. O.
Chey
,
M. Z.
Shoushtari
,
V.
Khrnovskyy
,
O.
Nur
, and
M.
Willander
, “
UV photo-detector based on p-NiO thin film/n-ZnO nanorods heterojunction prepared by a simple process
,”
J. Alloys Compd.
632
,
165
171
(
2015
).
5.
R.
Hasan
,
T.
Xie
,
S. C.
Barron
,
G.
Liu
,
N. V.
Nguyen
,
A.
Motayed
,
M. V.
Rao
, and
R.
Debnath
, “
Self-powered p-NiO/n-ZnO heterojunction ultraviolet photodetectors fabricated on plastic substrates
,”
APL Mater.
3
,
106101
(
2015
).
6.
H. K.
Li
,
T. P.
Chen
,
S. G.
Hu
,
X. D.
Li
,
Y.
Liu
,
P. S.
Lee
,
X. P.
Wang
,
H. Y.
Li
, and
G. Q.
Lo
, “
Highly spectrum-selective ultraviolet photodetector based on p-NiO/n-IGZO thin film heterojunction structure
,”
Opt. Express
23
,
27683
27689
(
2015
).
7.
R.
Karsthof
,
H.
von Wenckstern
, and
M.
Grundmann
, “
Semitransparent ZnO-based UV-active solar cells: Analysis of electrical loss mechanisms
,”
J. Vac. Sci. Technol., B
34
,
04J107
(
2016
).
8.
R.
Karsthof
,
P.
Räcke
,
H.
von Wenckstern
, and
M.
Grundmann
, “
Semi-transparent NiO/ZnO UV photovoltaic cells
,”
Phys. Status Solidi A
213
,
30
37
(
2016
).
9.
B.
Zhao
,
F.
Wang
,
H.
Chen
,
Y.
Wang
,
M.
Jiang
,
X.
Fang
, and
D.
Zhao
, “
Solar-blind avalanche photodetector based on single ZnO-Ga2O3 core-shell microwave
,”
Nano Lett.
15
,
3988
3993
(
2015
).
10.
H.
Chen
,
X.
Ma
,
J.
Zhang
,
Q.
Li
,
H.
Liu
,
Z.
Chen
,
G.
Chu
, and
S.
Chu
, “
Avalanche solar blind photodetectors with high responsivity based on MgO/MgZnO heterostructures
,”
Opt. Mater. Express
8
,
785
793
(
2018
).
11.
J.
Yu
,
C. X.
Shan
,
X. M.
Huang
,
X. W.
Zhang
,
S. P.
Wang
, and
D. Z.
Shen
, “
ZnO-based ultraviolet avalanche photodetectors
,”
J. Phys. D
46
,
305105
(
2013
).
12.
D.
Ji
,
B.
Ercan
,
G.
Benson
,
A. K. M.
Newaz
, and
S.
Chowdhury
, “
60 A/W high voltage GaN avalanche photodiode demonstrating robust avalanche and high gain up to 525 K
,”
Appl. Phys. Lett.
116
,
211102
(
2020
).
13.
J.
Kim
,
M. H.
Ji
,
T.
Detchprohm
,
J. H.
Ryou
,
R. D.
Dupuis
,
A. K.
Sood
, and
N. K.
Dhar
, “
AlxGa1−xN Ultraviolet avalanche photodiodes with avalanche gain greater than 105
,”
IEEE Photonics Technol. Lett.
27
,
642
645
(
2015
).
14.
Y.
Huang
,
D. J.
Chen
,
H.
Lu
,
K. X.
Dong
,
R.
Zhang
,
Y. D.
Zheng
,
L.
Li
, and
Z. H.
Li
, “
Back-illuminated separate absorption and multiplication AlGaN solar-blind avalanche photodiodes
,”
Appl. Phys. Lett.
101
,
253516
(
2012
).
15.
L.
Zhang
,
S.
Tang
,
H.
Wu
,
H.
Wang
,
Z.
Wu
, and
H.
Jiang
, “
GaN/Al0.1Ga0.9N-based visible-blind double heterojunction phototransistor with a collector-up structure
,”
Phys. Status Solidi A
214
,
1600821
(
2017
).
16.
M. L.
Lee
,
J. K.
Sheu
, and
Y. R.
Shu
, “
Ultraviolet bandpass Al0.7Ga0.3N/GaN heterojunction phototransistors with high optical gain and high rejection ratio
,”
Appl. Phys. Lett.
92
,
053506
(
2008
).
17.
X.
Qiu
,
Z.
Song
,
L.
Sun
,
Z.
Zhang
,
Z.
Lv
,
Q.
Wen
, and
H.
Jiang
, “
High-gain AlGaN/GaN visible-blind avalanche heterojunction phototransistors
,”
J. Mater. Sci.
31
,
652
657
(
2020
).
18.
L.
Zhang
,
S.
Tang
,
C.
Liu
,
B.
Li
,
H.
Wu
,
H.
Wang
,
Z.
Wu
, and
H.
Jiang
, “
Demonstration of solar-blond AlxGa1−xN-based heterojunction phototransistors
,”
Appl. Phys. Lett.
107
,
233501
(
2015
).
19.
W. L.
Jang
,
Y. M.
Lu
,
W. S.
Hwang
,
T. L.
Hsiung
, and
H. P.
Wang
, “
Point defects in sputtered NiO films
,”
Appl. Phys. Lett.
94
,
062103
(
2009
).
20.
H. L.
Chen
,
Y. M.
Lu
,
J. Y.
Wu
, and
W. S.
Hwang
, “
Effects of substrate temperature and oxygen pressure on crystallographic orientations of sputtered nickel oxide films
,”
Mater. Trans.
46
,
2530
2535
(
2005
).
21.
J. E.
Sanchez
,
U.
Santiago
,
A.
Benitez
,
M. J.
Yacaman
,
F. J.
Gonzalez
, and
A.
Ponce
, “
Structural analysis of the epitaxial interface Ag/ZnO in hierarchical nanoantennas
,”
Appl. Phys. Lett.
109
,
153104
(
2016
).
22.
J. D.
Hwang
and
G. S.
Lin
, “
Single- and dual-wavelength photodetectors with MgZnO/ZnO metal-semiconductor-metal structure by varying the bias voltage
,”
Nanotechnology
27
,
375502
(
2016
).
23.
L. P.
Peng
,
L.
Fang
,
X. F.
Yang
,
Y. J.
Li
,
Q. L.
Huang
,
F.
Wu
, and
C. Y.
Kong
, “
Effect of annealing temperature on the structure and optical properties of In-doped ZnO thin films
,”
J. Alloys Compd.
484
,
575
579
(
2009
).
24.
S.
Tang
,
L.
Zhang
,
H.
Wu
,
C.
Liu
, and
H.
Jiang
, “
Improved performance of ultraviolet AlGaN/GaN npn HPTs by a thin lightly-doped n-AlGaN insertion layer
,”
AIP Adv.
9
,
125239
(
2019
).
25.
M.
Zhu
,
J.
Chen
,
J.
Xu
, and
X.
Li
, “
Optimization of GaN/InGaN heterojunction phototransistor
,”
IEEE Photonics Technol. Lett.
29
,
373
376
(
2017
).
26.
R.
Debnath
,
T.
Xie
,
B.
Wen
,
W.
Li
,
J. Y.
Ha
,
N. F.
Sullivan
,
N. V.
Nguyen
, and
A.
Motayed
, “
A solution-processed high-efficiency p-NiO/n-ZnO heterostructure photodetector
,”
RSC Adv.
5
,
14646
14652
(
2015
).
27.
C. H.
Ji
,
K. T.
Kim
, and
S. Y.
Oh
, “
High-detectivity perovskite-based photodetector using a Zr-doped TiOx cathode interlayer
,”
RSC Adv.
8
,
8302
8309
(
2018
).
28.
K. W.
Ang
,
M. B.
Yu
,
G. Q.
Lo
, and
D. L.
Kwong
, “
Low-voltage and high-responsivity germanium bipolar phototransistor for optical detections in the near-infrared regime
,”
IEEE Electron Device Lett.
29
,
1124
1127
(
2008
).
You do not currently have access to this content.