Gallium vacancies—common non-radiative defects in ternary GaAsP and quaternary GaNAsP nanowires

J E Stehr,I A Buyanova,R La,C W Tu,W M Chen,M Jansson

doi:10.1088/2632-959x/aba7f0

J E Stehr, I A Buyanova + Show 4 more

Open Access

https://doi.org/10.1088/2632-959x/aba7f0

Copy DOI

Abstract

Nanowires (NWs) based on ternary GaAsP and quaternary GaNAsP alloys are considered as very promising materials for optoelectronic applications, including in multi-junction and intermediate band solar cells. The efficiency of such devices is expected to be largely controlled by grown-in defects. In this work we use the optically detected magnetic resonance (ODMR) technique combined with photoluminescence measurements to investigate the origin of point defects in Ga(N)AsP NWs grown by molecular beam epitaxy on Si substrates. We identify gallium vacancies, which act as non-radiative recombination centers, as common defects in ternary and quaternary Ga(N)AsP NWs. Furthermore, we show that the presence of N is not strictly necessary for, but promotes, the formation of gallium vacancies in these NWs.

Highlights

Group III–V nanowires (NWs) have attracted a growing interest as building blocks for optoelectronic and photovoltaic applications [1,2,3,4,5,6]
In this work we use the optically detected magnetic resonance (ODMR) technique combined with photoluminescence measurements to investigate the origin of point defects in Ga(N)AsP NWs grown by molecular beam epitaxy on Si substrates
In this work we investigate the origin of point defects in Ga(N)AsP NWs and their role in carrier recombination by using the optically detected magnetic resonance (ODMR) technique in combination with photoluminescence (PL) measurements

Summary

Introduction

Group III–V nanowires (NWs) have attracted a growing interest as building blocks for optoelectronic and photovoltaic applications [1,2,3,4,5,6] Due to their one-dimensional geometry, the NWs can exhibit structural [7, 8], electrical [9] and photonic properties [10,11,12,13] that are different from and are often superior to their bulk and thin-film counterparts. Among III–V compounds and related alloys, GaAsP is of particular interest This is because the bandgap energy of this material can be tuned within the 1.4–2.3 eV range, attractive for using this alloy in multi-junction solar cells [5, 14, 15]. The highest efficiency of these devices is predicted [22] when the total bandgap energy is 1.95 eV, making GaNAsP attractive for applications in multi-junction and intermediate-band solar cells [16, 17]

Methods

Results

Conclusion