Threading dislocation densities in semiconductor crystals: a geometric approach

TL;DR

This paper presents a geometric model explaining how uniform screw dislocation densities in semiconductors create bound states that increase carrier concentration and introduce new recombination paths, affecting semiconductor properties.

Contribution

It introduces a novel geometric approach linking dislocation densities to quantum bound states in semiconductors, providing insight into shallow level formation.

Findings

Dislocation densities act as effective magnetic fields.

Bound states form within the band gap due to dislocations.

Carrier concentration increases in dislocation-rich regions.

Abstract

In this letter, we introduce a geometric model to explain the origin of the observed shallow levels in semiconductors threaded by a dislocation density. We show that a uniform distribution of screw dislocations acts as an effective uniform magnetic field which yields bound states for a spin-half quantum particle, even in the presence of a repulsive Coulomb-like potential. This introduces energy levels within the band gap, increasing the carrier concentration in the region threaded by the dislocation density and adding additional recombination paths other than the near band-edge recombination.