Microtubes and nanomembranes by ion-beam-induced exfoliation of β-Ga2O3

This paper reports an innovative process to fabricate β -Ga 2 O 3 microtubes and nanomembranes based on ion implantation in (100)-oriented single-crystals. We show that the detachment and rolling-up of a thin surface layer, forming a microtube, can be promoted by the implantation-induced strain profile. The strain-disorder interplay was investigated in detail for Cr-implanted β -Ga 2 O 3 with complementary methods, showing an excellent agreement between experiments and simulations, and suggesting an exfoliation mechanism that is correlated with the anisotropic nature of the β -Ga 2 O 3 monoclinic system and its easy-cleavage planes. Moreover, these microtubes are transferrable to other substrates and can be unrolled under thermal annealing, resulting in nanomembranes with bulk-like crystalline quality. A study of the evolution of the implantation-induced damage under annealing showed a remarkable recovery at moderate temperatures (∼500°C). This method thus shows potential for the scalable production of nanomembranes and can be realized employing any ion species, providing simultaneous doping.