Revisiting ZnO/InP Heterojunction Solar Cells

Authors

Kyle H. Montgomery, Qiong Nian, Xin Zhao, Haoyu U. Li, Gary J. Cheng, Thomas N. Jackson, J. M. Woodall

Publication

55th Electronic Materials Conference, South Bend, IN, 2013.

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Abstract

Ongoing work in the field of solar photovoltaics primarily centers on either increasing cell efficiency with minimal increase in production cost or reducing production costs while maintaining cell efficiency. InP is closest to the ideal for a single junction solar cell in terms of its band gap and absorption coefficient. However, InP has traditionally been too expensive to commercialize on a large scale using bulk substrates. In this work, we investigated aluminum-doped zinc oxide (AZO) on p-type InP substrates as a novel, low-cost alternative that could have application to poly-crystalline III-V-based solar cells. Due to surface states, the Fermi level in InP has been shown to be pinned close to the conduction band, necessitating the need to use p-type InP with a transparent conducting oxide (TCO) having a large work function, such as in the case of ZnO. Previous work by Pande demonstrated an efficiency of 6.6% under AM 1 illumination for a similar ZnO/InP heterojunction. In this work, by using pulsed laser deposition (PLD), degradation at the oxide/InP interface is reduced compared to reactive sputtering as used prior. In addition, the effect of using direct pulsed laser recrystallization (DPLR) technique after AZO deposition on InP was evaluated. Prior work has shown decreased resistivity and increased carrier mobility in AZO films treated by this method, although the effects of DPLR of AZO directly on InP have not been directly studied before.

Keywords

zinc oxide, indium phosphide, photovoltaics, solar cells, thin films.

DOI

Citation

K. H. Montgomery, Q. Nian, X. Zhao, H. U. Li, G. J. Cheng, T. N. Jackson, and J. M. Woodall, “Revisiting ZnO/InP Heterojunction Solar Cells,” presented at the 55th Electronic Materials Conference, South Bend, IN, 2013.