Improving photoresponsivity in GaAs film grown on Al-induced-crystallized Ge on an insulator

T Nishida,T Suemasu,K Toko

doi:10.1063/1.5138677

Abstract

The highest recorded photoresponsivity in polycrystalline GaAs films on glass has been updated by precisely controlling the growth temperature of GaAs on a Ge seed layer formed by Al-induced layer exchange. X-ray diffraction and electron backscatter diffraction analyses showed that large-grained (&gt;100 µm) GaAs (111) films epitaxially grew from the Ge layer above 510 °C. According to energy dispersive x-ray and Raman spectra, 550 °C was the optimum growth temperature that allowed for the growth of high-quality GaAs film with a stoichiometric composition. Reflecting the high crystallinity, the internal quantum efficiency reached 90% under a bias voltage of 0.3 V. Low-temperature GaAs films grown on inexpensive substrates will make the development of advanced solar cells that achieve both high efficiency and low cost possible.

Highlights

The direct synthesis of polycrystalline GaAs films on inexpensive substrates has been studied for decades as a means of developing solar cells that simultaneously achieve high efficiency and low cost
Simple techniques, including vacuum deposition,3–9 crystallization of amorphous films,10–12 and chemical synthesis,13,14 have allowed for polycrystalline GaAs films on insulators; a photoresponse has never been obtained mainly owing to carrier recombination at grain boundaries, which often exists in the films
We investigate the effects of GaAs growth temperature on the quality of polycrystalline GaAs films seeded by Al-induced layer exchange (ALILE)-Ge

Summary

Introduction

The direct synthesis of polycrystalline GaAs films on inexpensive substrates has been studied for decades as a means of developing solar cells that simultaneously achieve high efficiency and low cost.1,2 Simple techniques, including vacuum deposition,3–9 crystallization of amorphous films,10–12 and chemical synthesis,13,14 have allowed for polycrystalline GaAs films on insulators; a photoresponse has never been obtained mainly owing to carrier recombination at grain boundaries, which often exists in the films.15,16.

Results

Conclusion