Synthesis of metastable, semiconducting Ge-Sn alloys by pulsed UV laser crystallization

Abstract

Thin microcrystalline films of the metastable semiconducting alloy Ge1−xSnx (x≊0.22) have been formed using excimer laser radiation to crystallize amorphous sputtered films on glass and semiconducting crystalline substrates. X-ray diffraction, electroreflectance, and Raman spectroscopy have been used to characterize the semiconducting material which is stable to at least 200 °C. The study demonstrates the possibility of extending earlier studies of amorphous Ge1−xSnx alloys into a crystalline regime with a direct band-gap variable with x from 0 up to about 0.5 eV. The crystallization technique is potentially applicable to the formation of other metastable semiconducting compounds of device potential.