Ion-Beam Modification of Metastable Gallium Oxide Polymorphs

TL;DR

This study investigates how ion irradiation affects different polymorphs of gallium oxide, revealing that the alpha phase exhibits higher radiation tolerance than other phases, which is crucial for doping and electronic applications.

Contribution

It provides the first detailed analysis of structural changes in gallium oxide polymorphs under ion irradiation, highlighting the alpha phase's superior radiation resistance.

Findings

Alpha-phase gallium oxide shows no noticeable deformation under ion irradiation.

Inclusions of alpha-prime phase expand along the surface normal after irradiation.

The alpha phase demonstrates higher radiation tolerance compared to other polymorphs.

Abstract

Gallium oxide with a corundum structure ({\alpha}-Ga2O3) has recently attracted great attention in view of electronic and photonic applications due to its unique properties including a wide band gap exceeding that of the most stable beta phase (\b{eta}-Ga2O3). However, the lower thermal stability of the {\alpha}-phase at ambient conditions in comparison with the \b{eta}-phase requires careful investigation of its resistance to other external influences such as ion irradiation, ion doping, etc. In this work, the structural changes under the action of Al+ ion irradiation have been investigated for a polymorphic gallium oxide layers grown by hydride vapor phase epitaxy on c-plane sapphire and consisting predominantly of {\alpha}-phase with inclusions of {\alpha}(\k{appa})-phase. It is established by the X-ray diffraction technique that inclusions of {\alpha}(\k{appa})-phase in the irradiated layer undergo the expansion along the normal to the substrate surface, while there is no a noticeable deformation for the {\alpha}-phase. This speaks in favor of the different radiation tolerance of various Ga2O3 polymorphs, especially the higher radiation tolerance of the {\alpha}-phase. This fact should be taken into account when utilizing ion implantation to modify gallium oxide properties in terms of development of efficient doping strategies.