Quantum-well states and discontinuities in opto-electrical characteristics of SCH lasers

Abstract

Computer simulations with Synopsys' Sentaurus TCAD of opto-electrical characteristics of separate-confinement heterostructure laser based on AlGaAs are used as an example to study the role of the width and depth of Quantum Well (QW) active region on laser characteristics, I-V and I-L, below and above the lasing threshold. The device properties depend on both, the number of bound QW states and on closeness of the highest bound states to conduction or valence band offset. The lasing action may not exist at certain widths or hights of QW, the threshold current is a discontinuous function of these parameters. The effects are more pronounced at low temperatures. Discontinuities in characteristics may be observed at certain conditions in temperature dependencies of laser parameters.