| Autor: |
Chen, Xiao Jun, Hwang, Jun-Seo, Perillat-Merceroz, Guillaume, Landis, Stefan, Martin, Brigitte, Dang, Daniel Le Si, Eymery, Joël, Durand, Christophe |
| Rok vydání: |
2011 |
| Předmět: |
|
| Zdroj: |
Journal of Crystal Growth 322, 1 (2011) 15 |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1016/j.jcrysgro.2011.03.007 |
| Popis: |
Selective area growth of GaN nanostructures has been performed on full 2" c-sapphire substrates using Si3N4 mask patterned by nanoimprint lithography (array of 400 nm diameter circular holes). A new process has been developed to improve the homogeneity of the nucleation selectivity of c-oriented hexagonal prismatic nanostructures at high temperature (1040\circ C). It consists of an initial GaN nucleation step at 950 \circ C followed by ammonia annealing before high temperature growth. Structural analyses show that GaN nanostructures are grown in epitaxy with c-sapphire with lateral overgrowths on the mask. Strain and dislocations are observed at the interface due to the large GaN/sapphire lattice mismatch in contrast with the high quality of the relaxed crystals in the lateral overgrowth area. A cathodoluminescence study as a function of the GaN nanostructure size confirms these observations: the lateral overgrowth of GaN nanostructures has a low defect density and exhibits a stronger near band edge (NBE) emission than the crystal in direct epitaxy with sapphire. The shift of the NBE positions versus nanostructure size can be mainly attributed to a combination of compressive strain and silicon doping coming from surface mask diffusion. |
| Databáze: |
arXiv |
| Externí odkaz: |
|
