An Ab Initio Study of Aluminium self-compensation in Bulk Silicon

TL;DR

This study uses density functional theory to investigate how aluminium dopants behave in silicon, revealing conditions under which they form electrically active pairs or self-compensate, impacting silicon doping strategies.

Contribution

It provides new insights into the atomic and electronic structures of aluminium dopant pairs in silicon, highlighting the role of spin states in their electrical activity.

Findings

Aluminium dopant pairs can bond in high spin states.

High spin state dopant pairs are electrically active.

Low spin state dopant pairs are self-compensating.

Abstract

We have used density functional theory to study the energetics and electronic structure of aluminium dopants in crystalline silicon. We present data regarding the atomic and electronic structure and properties of pairs of substitutional aluminium dopants. We find that pairs of dopants, when occupying nearest neighbouring subsitutional sites in a high spin state, can bond to form aluminium pairs. This suggests that such a configuration of dopants will be electrically active when made to occupy a high spin state, whereas in the low spin state the neighbouring dopant pairs are found to be self compensating.