Stark-Effect Scattering in Rough Quantum Wells

TL;DR

This paper investigates how electric fields cause Stark-effect scattering in rough quantum wells, affecting electron mobility, and identifies a quantum well width where scattering is minimized, providing insights for optimizing semiconductor device performance.

Contribution

It introduces a new scattering mechanism due to Stark shifts in rough quantum wells and analyzes its impact across different well widths and electric field strengths.

Findings

Existence of a quantum well width window with minimal scattering

Stark-effect scattering significantly impacts mobility in wide wells

Mobility degradation is severe in both narrow and wide wells due to this effect

Abstract

A scattering mechanism stemming from the Stark-shift of energy levels by electric fields in semiconductor quantum wells is identified. This scattering mechanism feeds off interface roughness and electric fields, and modifies the well known 'sixth-power' law of electron mobility degradation. This work first treats Stark-effect scattering in rough quantum wells as a perturbation for small electric fields, and then directly absorbs it into the Hamiltonian for large fields. The major result is the existence of a window of quantum well widths for which the combined roughness scattering is minimum. Carrier scattering and mobility degradation in wide quantum wells are thus expected to be equally severe as in narrow wells due to Stark-effect scattering in electric fields.