Disorder Induced Ordering in Gallium Oxide (DIOGO)

Recently, we showed that the accumulation of the radiation-induced disorder in gallium oxide crystals may result in paradoxical ordering of alternative lattice structures – called polymorphs – instead of chaotic disorganization, known as amorphization of materials. Concurrently, there were two novel properties observed: (i) atomically-sharp interfaces between different polymorph layers and (ii) unprecedently high radiation tolerance of this “disorder-engineered” structures. However, even though the results of this discovery were already published in two high-impact journals, specifically in Physical Review Letters 128, 15704(2022) and Nature Communications 14, 4855 (2023), the understanding of the underlying physical mechanisms is incomplete and potential practical applications of these novel structures are unexplored. Thus, we aim to undertake a systematic effort to understand the nature of the disorder-induced crystallization instead of amorphization, paving the way for functionalization of the “disorder-engineered” structures. For that matter we propose to use an arsenal of methods available within NorFab/NORTEM research infrastructures in Norway, reinforced by using international large-scale infrastructures and receiving inputs via collaborations. As such, our goals are ambitious, novel, credible, and cross-disciplinary, altogether leading towards very positive expected outcomes, aligning this project with the FRIPRO program objectives.

We aim to understand the nature of the disorder-induced crystallization instead of amorphization in Ga2O3, accompanied with formation of self-organized polymorph interfaces, potentially paving the way for functionalization of these new semiconductor structures. We start from our own set of preliminary data: (i) observation of ion irradiation induced ß-to-? polymorph transformation in Ga2O3, (ii) finding that ?/ß Ga2O3 interfaces fabricated by such processing exhibit very low lattice mismatch and (iii) discovery that as soon as ?-Ga2O3 forms, it demonstrates unprecedently high radiation tolerance. Starting from there, our objective is twofold. Firstly, we want to understand the fundamental mechanisms behind (i-iii) phenomena and gain a full control over the polymorph transformations. For that matter we propose to use an arsenal of methods available within NorFab/NORTEM research infrastructures in Norway, reinforced by using international large-scale infrastructures and receiving inputs via collaborations. Secondly, we plan to apply our fundamental findings to improve radiation tolerant and power electronics devices. This part of work is plausible because consistently with our preliminary device simulations there is a significant performance gain if including ?/ß Ga2O3 interfaces into the power device designs. Moreover, the device development is feasible, because we already made an initial demonstration of simplified, but operating ?/ß Ga2O3 diodes, shown to remain functionable when reference devices failed in the radiation tests. Thus, our objectives are credible making the project ambitious, novel, and cross-disciplinary, with very positive expected impacts.