TY - JOUR
T1 - Nonpolar and semipolar InGaN/GaN multiple-quantum-well solar cells with improved carrier collection efficiency
AU - Huang, Xuanqi
AU - Fu, Houqiang
AU - Chen, Hong
AU - Zhang, Xiaodong
AU - Lu, Zhijian
AU - Montes, Jossue
AU - Iza, Michael
AU - Denbaars, Steven P.
AU - Nakamura, Shuji
AU - Zhao, Yuji
N1 - Funding Information:
This work was supported by an Early Career Faculty grant from NASA's Space Technology Research Grants Program. The authors would like to express sincere gratitude to Mr. Salman Manzoor for the help in transmission and reflection measurements, to Dr. Jacob Becker for the help in IV and EQE measurements, and to Professor Yong-Hang Zhang at Arizona State University for access to his optoelectronics characterization.
Publisher Copyright:
© 2017 Author(s).
PY - 2017/4/17
Y1 - 2017/4/17
N2 - We demonstrate the nonpolar and semipolar InGaN/GaN multiple-quantum-well (MQW) solar cells grown on the nonpolar m-plane and semipolar (2021) plane bulk GaN substrates. The optical properties and photovoltaic performance of the nonpolar and semipolar InGaN solar cells were systematically studied, and the results were compared to the conventional polar c-plane devices. The absorption spectra, current density-voltage (J-V) characteristics, external quantum efficiency (EQE), and internal quantum efficiency (IQE) were measured for nonpolar m-plane, semipolar (2021) plane, and polar c-plane InGaN/GaN MQW solar cells. Nonpolar m-plane InGaN/GaN MQW solar cells showed the best performance across all devices, with a high open-circuit voltage of 2.32 V, a low bandgap-voltage offset of 0.59 V, and the highest EQE and IQE. In contrast, the polar c-plane device showed the lowest EQE despite the highest absorption spectra. This huge difference is attributed to the better carrier transport and collection on nonpolar m-plane devices due to the reduced polarization effects, which were further confirmed by bias-dependent EQE measurements and energy band diagram simulations. This study demonstrates the high potential of nonpolar and semipolar InGaN solar cells and can serve as guidance for the future design and fabrication of high efficiency III-nitride solar cells.
AB - We demonstrate the nonpolar and semipolar InGaN/GaN multiple-quantum-well (MQW) solar cells grown on the nonpolar m-plane and semipolar (2021) plane bulk GaN substrates. The optical properties and photovoltaic performance of the nonpolar and semipolar InGaN solar cells were systematically studied, and the results were compared to the conventional polar c-plane devices. The absorption spectra, current density-voltage (J-V) characteristics, external quantum efficiency (EQE), and internal quantum efficiency (IQE) were measured for nonpolar m-plane, semipolar (2021) plane, and polar c-plane InGaN/GaN MQW solar cells. Nonpolar m-plane InGaN/GaN MQW solar cells showed the best performance across all devices, with a high open-circuit voltage of 2.32 V, a low bandgap-voltage offset of 0.59 V, and the highest EQE and IQE. In contrast, the polar c-plane device showed the lowest EQE despite the highest absorption spectra. This huge difference is attributed to the better carrier transport and collection on nonpolar m-plane devices due to the reduced polarization effects, which were further confirmed by bias-dependent EQE measurements and energy band diagram simulations. This study demonstrates the high potential of nonpolar and semipolar InGaN solar cells and can serve as guidance for the future design and fabrication of high efficiency III-nitride solar cells.
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U2 - 10.1063/1.4980139
DO - 10.1063/1.4980139
M3 - Article
AN - SCOPUS:85018523878
SN - 0003-6951
VL - 110
JO - Applied Physics Letters
JF - Applied Physics Letters
IS - 16
M1 - 161105
ER -