The role of quantum-well states and carrier scattering times on discontinuities in opto-electrical characteristics of SCH lasers

TL;DR

This study uses drift-diffusion simulations to analyze how quantum well properties and carrier scattering times influence discontinuities in the electrical and optical characteristics of AlGaAs SCH lasers, especially near threshold conditions.

Contribution

It reveals the impact of quantum well width, depth, and carrier scattering times on laser discontinuities, providing new insights into device behavior under various conditions.

Findings

Discontinuities occur at specific QW widths and heights.

Carrier scattering time significantly affects the amplitude of discontinuities.

Temperature influences the prominence of these discontinuities.

Abstract

Drift-diffusion computer simulations model available in Synopsys' Sentaurus TCAD is used to study electrical, I-V, and optical, I-L, characteristics of separate-confinement heterostructure laser based on $AlGaAs$. We investigate the role of the width and depth of Quantum Well (QW) active region, 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, and the threshold current is a discontinuous function of these parameters. The effects are more pronounced at low temperatures. Discontinuities in characteristics are found, at certain conditions, in temperature dependencies as well. The carriers scattering time on QW is shown to have the crucial role on amplitude of discontinuities.