The improved photoresponse of the substrate-free InGaN solar cells with a bottom reflector

Chia Lung Tsai*, Guan Shan Liu, Chien Yu Wang, Ju Ping Huang, Jia Qing Lin

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations

Abstract

In this study, the laser lift-off (LLO) technique is used to fabricate the substrate-free InGaN thin-film solar cells (TF-SCs). The epitaxial structures consist of 8-pair In0.23Ga0.77N/GaN multiple-quantum-well (MOW), which is sandwiched between the p- and n-GaN to construct the conventional p-i (intrinsic layer)-n solar cells. After the LLO process to remove the sapphire substrate, a silver layer with reflectivity of 97% was deposited onto the bottom of cell to act as the metallic reflector. Under forward bias operation, the fabricated TF-SCs exhibit a low operating voltage of 3.34 V along with an ideality factor of 6 V. Both of which are comparable to their counterparts that reveals the electrical property of device does not damage after the LLO process. On the other hand, it is observed that the spectral response of the InGaN solar cells changes significantly as the incident wavelength below 510 nm. This wavelength corresponds to the energy transition (∼ 2.43 eV) between the first electron and hole energy level of the In 0.23Ga0.77N/GaN well. Since part of the unabsorbed photons can be re-reflected by the bottom reflector, the TF-SCs show the enhanced photoresponse as compared to the normal solar cells with the sapphire substrate. Finally, the conversion efficiency of the TF-SC is 1.6 times larger than the normal InGaN solar cell under one sunAM 1.5G spectrum.

Original languageEnglish
Title of host publication2009 34th IEEE Photovoltaic Specialists Conference, PVSC 2009
Pages2051-2054
Number of pages4
DOIs
StatePublished - 2009
Event2009 34th IEEE Photovoltaic Specialists Conference, PVSC 2009 - Philadelphia, PA, United States
Duration: 07 06 200912 06 2009

Publication series

NameConference Record of the IEEE Photovoltaic Specialists Conference
ISSN (Print)0160-8371

Conference

Conference2009 34th IEEE Photovoltaic Specialists Conference, PVSC 2009
Country/TerritoryUnited States
CityPhiladelphia, PA
Period07/06/0912/06/09

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