Previous attempts to grow AlN nanowires resulted in severely coalesced nanowire ensembles. Coalescence leads to crystal defects, foiling the conceptual advantage of nanowires over planar films. As a novel approach, we pioneer AlN nanowire growth by molecular beam epitaxy on sputtered metallic TiN films as substrates. TiN exhibits high chemical and thermal stability, which enables us to use an exceptionally high substrate temperature close to 1200 °C. The high substrate temperature promotes Al adatom diffusion, which in turn facilitates the formation of well-separated nanowires. Their high crystalline quality is evidenced by the observation of near-band-edge luminescence. Beyond the properties of the nanowires themselves, the metallic nature of the TiN film is highly beneficial for optoelectronic devices. The excellent electrical and thermal conductivity of this material improves charge injection and waste heat dissipation. Therefore, the growth of AlN nanowires on TiN introduced in our study opens up new possibilities for the fabrication of high quality AlN/(Al,Ga)N heterostructures emitting in the deep UV range.
|1||Author||M. Azadmand , T. Auzelle , J. Lähnemann , G. Gao , L. Nicolai , M. Ramsteiner , A. Trampert , S. Sanguinetti , O. Brandt , L. Geelhaar|
Self-assembly of well-separated AlN nanowires directly on sputtered metallic TiN films
|Source||Phys. Status Solidi RRL , 14 , 1900615 ( 2020 )|
: 10.1002/pssr.201900615 |