ZnO-based semiconductors with tunable band gap for solar sell applications

Naho Itagaki, K. Matsushima, D. Yamashita, Hyunwoong Seo, Kazunori Koga, Masaharu Shiratani

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In this study, we discuss the potential advantages of a new ZnO-based semiconductor, ZnInON (ZION), for application in multi quantum-well (MQW) photovoltaics. ZION is a pseudo-binary alloy of ZnO and InN, which has direct and tunable band gaps over the entire visible spectrum. It was found from simulation results that owing to the large piezoelectric constant, the spatial overlap of the electron and hole wave functions in the QWs is significantly small on the order of 10-2, where the strong piezoelectric field enhances the separation of photo generated carriers. As a result, ZION QWs have low carrier recombination rate of 1014-1018 cm-3s-1, which is much lower than that in conventional QWs such as InGaAs/GaAs QW (1019 cm-3s-1) and InGaN/GaN QW (1018-1018 cm-3s-1). The long carrier life time in ZION QWs (ə1/41μs) should enable the extraction of photo-generated carriers from well layers before the recombination, and thus increase Voc and Jsc. These simulation results are consistent with our experimental data showing that both Voc and Jsc of a p-i-n solar cell with strained ZION MQWs and thus the efficiency were increased by the superimposition of laser light with lower photon energy than the band gap energy of the QWs. Since the laser light contributed not to carrier generation but to the carrier extraction from the QWs, and no increase in Voc and Jsc was observed for relaxed ZION MQWs, the improvement in the efficiency was attributed to the long carrier lifetime in the strained ZION QWs.

Original languageEnglish
Title of host publicationOxide-Based Materials and Devices VI
EditorsFerechteh H. Teherani, David C. Look, David J. Rogers
PublisherSPIE
Volume9364
ISBN (Electronic)9781628414547
DOIs
Publication statusPublished - Jan 1 2015
EventOxide-Based Materials and Devices VI - San Francisco, United States
Duration: Feb 8 2015Feb 11 2015

Other

OtherOxide-Based Materials and Devices VI
Country/TerritoryUnited States
CitySan Francisco
Period2/8/152/11/15

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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