Influence of doping of Ga0.68Al0.32As on its cathodoluminescence and threshold current density of a laser pumped by an electron beam

A study was made of the influence of doping of Ga/sub 0.68/Al/sub 0.32/As solid solutions with tellurium (from 5 x 10/sup 16/ to 1 x 10/sup 18/ cm/sup -3/) or zinc (from 4 x 10/sup 17/ to 1 x 10/sup 19/ cm/sup -3/) on the radiative characteristics. The cathodoluminescence intensity and the threshold current density of an electron-beam-pumped laser deteriorated greatly as a result of doping with tellurium in amounts in excess of 3 x 10/sup 17/ cm/sup -3/. This was attributed to a nonradiative recombination channel in which an impurity level or a band associated with an indirect L minimum of the conduction band participated. In the case of zinc doping the cathodoluminescence intensity and the threshold current density of a laser were practically indepedent of the dopant concentration. The zinc-doped samples had a lower threshold current density (50 mA/cm/sup 2/ at T = 90 /sup 0/K and 0.9A/cm/sup 2/ at T = 300 /sup 0/K) than the samples with n-type conduction.