Abstract

Quantum wire structures, which provide quantum confinement in two dimensions, have undergone extensive study and development for their interesting physical phenomena and potential device applications.^1-4 Obviously the main purpose of fabricating quantum wires is to generate semiconductor heterastructures with properties superior to quantum wells, One of the drawbacks in the quantum wire lasers compared to quantum well laser, however, is its small optical confinement factor, Γ. As a matter of fact, there is a tradeoff between Γ and quantum confinement. To overcome such a problem, superlattice quantum wires³ or multilayer quantum wires⁴ structures have been proposed. However, a quantitative analysis of under what conditions a quantum wire has an optimum Γ is still lacking. The purpose of this paper is to investigate this issue and provide guidelines toward an optimum quantum wire geometry. This is a very complicated task because of the large number of parameters available for optimization and the complexity of the calculations required. In this paper, a systematic method to estimate an optimum Γ wall be presented. For a quantitative analysis, this method will be applied to investigate the threshold current of a laser whose active area consists of an array of rectangular quantum wires in GaAs/AlGaAs system. The effect of various lateral dimensions on the threshold current is investigated and optimum geometry that results in the maximum improvement of the threshold current are determined. In the calculations valence band intermixing effects are taken into account.

© 1993 Optical Society of America