Sn doped β-Ga2O3 and β-Ga2S3 nanowires with red emission for solar energy spectral shifting

Abstract

Sn doped β-Ga2O3 nanowires have been grown on Si(001) via the vapor-liquid-solid mechanism at 800 °C over a broad range of compositions. These have a monoclinic β-Ga2O3 crystal structure and minimum resistances for 1-2 at. % Sn but we observe the emergence of tetragonal rutile SnO2 which dominates with increasing content of Sn. All of the nanowires exhibited photoluminescence at 2.7 eV but a red shift of the emission occurred from 2.7 eV to 1.8 eV after post growth processing under H2S above 500 °C. The red emission is related to deep donor to acceptor transitions and the formation of monoclinic β-Ga2S3 and has been exploited for spectral shifting in a Si solar cell resulting into an increase of the power conversion efficiency from 7.2% to 8.3%. © 2015 AIP Publishing LLC.