Seminarium Fizyki Ciała Stałego

A specifically attractive benefit offered by the self-assembled formation of GaN nanowires (NWs) in plasma-assisted molecular beam epitaxy (PAMBE) is the possibility of creating vertically well aligned and single-crystalline NWs even on amorphous layers. Thus the very limited restrictions in terms of the choice of substrate could substantially widen the range of applications based on GaN NWs. However, an in-depth understanding on the self-assembled formation of GaN NWs on non-crystalline layers is still far from being complete.In this talk the mechanisms of spontaneous nucleation and PAMBE growth of GaN NWs on a-AlxOy buffer layers will be presented and compared with analogous processes on nitridated Si substrates (the most common substrate for GaN NWs). As will be shown, by proper choice of growth conditions, GaN NWs with excellent structural and optical properties can be obtained on a-AlxOy buffer layers. In this way, our results pave the way to crystallization of high quality GaN NWs on a large variety of substrates, in principle on any substrate, provided it is compatible with PAMBE technology and its surface is covered by a thin a-AlxOy buffer layer. In the second part of the talk, I will focus on selective area growth (SAG) of GaN NWs on a-AlxOy nucleation layers. In particular, an important role of Ga adatom surface diffusion for homogeneity of NW lengths in SAG will be discussed. Our findings demonstrate that nucleation and growth kinetics in SAG depends on the size of the mask pattern, which makes it very different from growth on the equivalent planar layers. UwagaSeminarium w trybie zdalnympatrz instrukcja :instrukcja: (pdf file)AttentionThe seminar in the remote modesee instruction :instruction: (pdf file)