Abstract

We observe saturation of cathodoluminescence (CL) from GaAs/AlGaAs single quantum well wires (QWWs) at high excitation intensity. The GaAs/AIGaAs QWWs were fabricated by electron-beam lithography, selective gallium ion implantation, and annealing.¹ Single QWWs were excited with a cw or pulsed 5-keV electron beam, and the resulting CL is detected by cw or subnanosecond time-delayed-coincidence photon counting. At 20 K and low excitation intensity the CL spectrum shows a peak at 1.65 eV due to the QWW and a weaker peak at 1.7 eV due to carriers excited in the surrounding implanted material. As the excitation intensity is increased, the lower energy peak broadens on the high-energy side and eventually saturates in intensity at a density of 8 × 10¹⁷/cm³, whereas the CL from the implanted or large masked regions saturates at the higher density of 4 × 10¹⁸/cm³. We attribute the saturation to band­filling. Time-resolved CL measurements are discussed. We report the first observation of CL from QWWs at room temperature. The CL intensity of the QWWs is comparable with that of the implanted regions. Both are an order of magnitude weaker than that of the unimplanted quantum well.

© 1988 Optical Society of America