Controlling Mn Depth Profiles in GaMnAs During High-Temperature Molecular Beam Epitaxial Growth

TL;DR

This study demonstrates that by adjusting the Mn cell temperature during high-temperature MBE growth of GaMnAs, researchers can control the Mn depth profile, reducing diffusion effects and tuning concentration gradients.

Contribution

It introduces a method to control Mn depth profiles in GaMnAs during high-temperature MBE growth by varying Mn cell temperature ramp rates.

Findings

Mn cell temperature ramp rate affects Mn depth profile slope

Controlling Mn deposition rate mitigates Mn diffusion

Mn concentration profile can be tuned from negative to positive

Abstract

Mn-doped GaAs thin films were grown at a high substrate temperature of 580 C. During the growth process, the Mn cell temperature was ramped at different rates, resulting in a variety of different Mn concentration depth profile slopes, as measured using dynamic secondary ion mass spectrometry (SIMS). Results show that controlling the Mn deposition rate via temperature during molecular beam epitaxy (MBE) growth can mitigate the effect of Mn atoms diffusing toward the surface. Most importantly, the slope of the Mn concentration as a function of depth inside the sample can be tuned from negative to positive.