FABRICATION OF GERMANIUM NANOWIRES BY OBLIQUE ANGLE DEPOSITION

Abstract

In this work, the effects of flux angle, substrate temperature and deposition rate on obliquely deposited germanium ( Ge ) films have been investigated. We observed that the porosity of the film increased as the flux angle became more oblique. It was also possible to obtain polycrystalline Ge films at a substrate temperature of 200°C when deposition was performed using an oblique angle of 87° as compared to normal incident deposition. Raman spectroscopy results indicated that a higher substrate temperature during deposition led to an increase in crystallinity of the film. Agglomeration of the Ge film was reduced at a lower deposition rate and it was possible to obtain isolated polycrystalline Ge nanowires when the deposition was carried out with the vapor flux inclined at 87° to the substrate normal for substrate temperatures between 250°C to 300°C and with a deposition rate of 0.2–1.5 Å/s. Subsequent rapid thermal annealing of such nanowires resulted in the formation of facetted crystallites.