Threshold Requirements and Carrier Interaction Effects in GaAs Platelet Lasers (77°K)

Abstract

The experimentally observed thresholds for laser operation of optically pumped GaAs platelets are presented. The measurements were performed on uniformly doped samples of p‐type, n‐type, and compensated crystal (doping range 10¹⁴/cm³≤n, p≤10²⁰/cm³). The observed thresholds are considerably lower than previously measured or predicted and exhibit no essential dependence upon impurity concentration. The 16‐meV shift of laser photon energy from bandgap in lightly doped GaAs is ascribed, as before, to electron‐hole‐lattice (EHL) interactions. Based upon the results of platelet laser threshold data and photon energy data, a comparison is made of the relative strength of the various EHL interaction mechanisms. If Coulomb interaction and dielectric screening can be ignored, over a certain doping range a remarkable fit of the photon energy data is afforded by the electron‐electron interaction mechanism.