Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8149096 | Journal of Crystal Growth | 2018 | 29 Pages |
Abstract
Droplet Epitaxy of AlGaN nanostructures was investigated in this work. Growth was carried out by Plasma Assisted Molecular Beam Epitaxy (PA-MBE) under extreme group III rich conditions, where the excess metal remained on the growth surface and formed nanoscale metallic droplets due to the interplay of surface energy, surface diffusion and desorption, all of which are strongly dependent on the relative arrival rates of gallium and aluminum and the substrate temperature. Intermittent exposure of this metallic film to active nitrogen forms various types of nanostructures, whose morphology, composition and luminescence properties were evaluated. Our results indicate that for AlN, the droplet epitaxy process forms random arrays of uniform well oriented [0 0 0 1] nanorods with a height of â¼1â¯Âµm and a diameter of 250â¯nm. For AlGaN grown under excess gallium, and intermittent exposure to the active plasma, structures with diameters of 200â¯Âµm to 600â¯Âµm and a height of 80â¯nm were observed. We report the spontaneous formation of lateral concentric heterostructures under these conditions. A single photoluminescence (PL) peak was observed at about 260â¯nm with a room temperature to 4â¯K intensity ratio of â¼25%.
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Condensed Matter Physics
Authors
Chirantan Singha, Sayantani Sen, Pallabi Pramanik, Mainak Palit, Alakananda Das, Abhra Shankar Roy, Susanta Sen, Anirban Bhattacharyya,