Crystalline quality of GaAs_1−x Bi _x grown below 250 °C using molecular beam epitaxy

Abstract

This study revealed crystalline quality of the dilute bismide alloy GaAs1-x Bi x grown on a GaAs(001) substrate below 250°C using molecular beam epitaxy. The substrate temperature and As flux played a dominant role in tuning the crystal structure between amorphous and single crystalline GaAs1-x Bi x , as well as in the Bi introduction in GaAs below 250°C. Sample characterization demonstrated a substrate temperature of 250°C produced single crystalline ~200 nm thick GaAs0.982Bi0.018 with clear X-ray diffraction fringes, while the lower substrate temperature of 180°C yielded an amorphous film. Rutherford backscattering spectrometry showed sufficient As supply at the growing surface provides uniform Bi distribution.