TEMPERATURE-DEPENDENCE OF CATHODOLUMINESCENCE FROM THIN GAAS-ALGAAS MULTIPLE-QUANTUM WELLS

The temperature dependence of the cathodoluminescence (CL) intensity o riginating from GaAs-Al0.3Ga0.7As multiple quantum wells has been meas ured between 5 and 300 K. The CL intensity drops exponentially by two orders of magnitude above 100 K with an activation energy of 83 meV be tween 140 and 200 K and 145 meV between 250 and 300 K. These energies are comparable to the effective barrier height of an electron or hole and an exciton, respectively. The decrease of the CL intensity is ther efore attributed to thermal re-emission of carriers and excitons out o f the quantum well.