Project name: Defect transformations in ion-bombarded GaN. The role of the internal electric field.

Project acronym: DIGaN

Project funding: international project co-funded by MEiN.

Additional information: the project is carried out within the framework of the international programme Laboratory of Accelerators and Radiation Technologies (LATR), ULisboa accelerator system, on the basis of a contract concluded with an international organisation or a foreign entity: Laboratório de Aceleradores e Tecnologias de Radiação (LATR) with No. LATR/2022/01.

Project Description:

The DIGaN project involves a novel approach to the analysis of damage accumulation and transformation in GaN crystals exposed to ion bombardment, with a particular focus on unconventional N-polar structures. The study will be carried out on high-quality dislocation-free GaN samples grown in Unipress/Ammono by an ammonothermal method, with low dislocation density, available in Ga- and N-polar orientations. Damage accumulation in GaN crystals bombarded with 300 keV Ar ions will be studied using a combined experimental and computational (simulation) approach. RBS/C will be carried out in international collaboration with the LATR institute in Portugal. The RBS/C data will be analysed using MC simulations in the McChasy code and supported by molecular dynamics simulations. Geometrical parameters of linear defects will be used as input in the McChasy code. The aim of the project is to determine the kinetics of damage accumulation in GaN as a result of ion bombardment, which will reveal a plastic transformation threshold above which reduction of structural defects is almost impossible even by thermal annealing. In addition, Raman spectroscopy will be used to assess potential phase changes in irradiated materials.