Polarity-Induced Selective Area Epitaxy of GaN Nanowires
详细信息 查看全文
- 作者：Ziani de Souza Schiaber ; Gabriele Calabrese ; Xiang Kong ; Achim Trampert ; Bernd Jenichen ; José Humberto Dias da Silva ; Lutz Geelhaar ; Oliver Brandt ; Sergio Fernández-Garrido
- 刊名：Nano Letters
- 出版年：2017
- 出版时间：January 11, 2017
- 年：2017
- 卷：17
- 期：1
- 页码：63-70
- 全文大小：611K
- ISSN：1530-6992
文摘
We present a conceptually novel approach to achieve selective area epitaxy of GaN nanowires. The approach is based on the fact that these nanostructures do not form in plasma-assisted molecular beam epitaxy on structurally and chemically uniform cation-polar substrates. By in situ depositing and nitridating Si on a Ga-polar GaN film, we locally reverse the polarity to induce the selective area epitaxy of N-polar GaN nanowires. We show that the nanowire number density can be controlled over several orders of magnitude by varying the amount of predeposited Si. Using this growth approach, we demonstrate the synthesis of single-crystalline and uncoalesced nanowires with diameters as small as 20 nm. The achievement of nanowire number densities low enough to prevent the shadowing of the nanowire sidewalls from the impinging fluxes paves the way for the realization of homogeneous core-shell heterostructures without the need of using ex situ prepatterned substrates.