Microstructure and electronic characterization of InGaAs containing layers of self-assembled ErAs nanoparticles

Abstract

We report the growth by molecular-beam epitaxy of a composite epitaxial material consisting of layers of semimetallic ErAs particles embedded in an In 0.53Ga 0.47As matrix. The ErAs particles were found to be 14±3 A ̊ high (∼4 monolayers) and varied in area depending on amount of ErAs deposited. The material was found to be strongly n-type for depositions less than one-half of a monolayer. As the deposition of ErAs increases, the lateral size and density of the particles also increases, resulting in a more rapid freeze out of the electrons and reduction of the free electron concentration at 300 K . We find the free electron concentration can be further reduced by compensation with beryllium, leading to more resistive material.