Abstract:
A study was made of the influence of doping of Ga0.68Al0.32As solid solutions with tellurium (from 5×1016 to 1×1018 cm–3) or zinc (from 4×1017 to 1×1019 cm–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 3×1017 cm–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/cm2 at T = 90 K and 0.9 A/cm2 at T = 300 K) than the samples with n-type conduction.