Low temperature growth and characterization of ZnSe films grown on GaAs

Abstract

Metalorganic vapor phase epitaxy (MOVPE) growth experiments of ZnSe on GaAs (100) are described using ditertiary butylselenide as the selenium source. The growth temperature was varied between 300 and 400°C and the growth rate was determined. Below a vapor pressure ratio P_Se/P_Zn of about 5, the selenium is the growth limiting component. The quality of the samples was analyzed by Nomarski microscopy, x-ray diffraction, high resolution transmission electron microscopy, and photoluminescence. Although the selenium-precursor was not specially purified, a sharp excitonic luminescence appears in samples grown at 400°C. The MOVPE growth of ZnSe still suffers from prereactions when H₂Se is used. The optimum growth is above 450°C even with precursors as DMSe or DESe which are less harmful than the hydride. This paper reports results obtained with a novel selenium-precursor: ditertiarybutylselenide.¹