Abstract

Quantum well intermixing (QW1) offers a technologically very important capability of altering the quantum-well (QW) shape and composition by post-growth processing. The impurity-free vacancy diffusion (IFVD) technique is of particular interest for fabrication of integrated optoelectronic circuits, as it allows bandgap tunability with minimal modification of as-grown doping profiles and without irradiation-induced damage accompanying ion implantation. Quality of intermixed material is an issue of major concern for device fabrication. Due to small size of QWs, the interdiffusion process cannot be measured directly and has to be studied using indirect methods. Although optical measurements such as photoluminescence, photoconductivity, transmission spectroscopy, photoreflectance, and Raman spectroscopy could provide information about the material quality, the ultimate test is to fabricate diode lasers and compare their performance to similar devices fabricated without intermixing. In this paper, we report fabrication and characterization of otherwise identical diode lasers with non-intermixed and intermixed active regions. Measured characteristics of these lasers are used to extract information about changes in threshold current density, internal optical loss, internal quantum efficiency, material gain, etc., introduced by the IFVD process.

© 2002 Optical Society of America