Nano-structural Characteristics and Optical and Electrical Properties of Obliquely Deposited Cuprous Azide Thin Films

Abstract

Cuprous azide films were prepared using oblique angle deposition of Cu at 40° and post-annealed with the flow of nitrogen at three different temperatures. This deposition angle provides the highest void fraction according to the published literature on the basis of rearrangement of atoms resulting from the diffusion or thermal vibration and the available crystallographic sites and surface energy on the substrate/growing film surface for relaxation of an adatom. Structural characteristics of the films were obtained using atomic force microscopy and field emission scanning electron microscopy while their crystallography was investigated by x-ray diffraction analysis. Optical spectra of the samples were measured from which optical constants were deduced. The direct band gap energies were obtained and compared with the reported theoretical calculations and experimental results. The band gap energies obtained from the process of plotting (αhυ)2 versus hυ are in agreement with the reported values in the literature. Band gap energies obtained from dT/dλ versus hυ eV method are in agreement with experimental values and with the theoretical band gap energy of 4.1 eV as well as those obtained from (αhυ)2 versus hυ method, while those obtained from dR/dλ versus hυ eV are in good agreement with theoretical band gap energy of 3.86 eV.