Cu doping effect on characterization of nano crystalline SnSe thin films

A thin film of (SnSe) and SnSe:Cu with various Cu ratio (0,3,5 and 7)% have been prepared by thermal evaporation technique with thickness 400±20 nm on glass substrate at (R.T). The effect of Cu dopants concentration on the structural, morphological, optical and electrical properties of (SnSe) Nano crystalline thin films was explored by using X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS), UV–Vis absorption spectroscopy and Hall Effect measurement respectively. X-ray diffraction analysis reveal the polycrystalline nature of the all films deposited with orthorhombic structure which possess a preferred orientation along the (111) plane. The crystalline sizes of the films vary in the range of (18.167– 25.91) nm, depending on the Cu doping ratio. The SEM study show that the film exhibit growth of small grains and the morphologies of SnSe could be changed from spherical grains to platelet-like particles. The AFM investigations show that the films grain size vary in the range (60.12 to 70.59) nm with increasing Cu doping ratio. The optical measurements on un doped and Cu doped SnSe thin films indicate that the samples have direct transition with an optical band gap of (1.3 –1. 5) eV and the absorption coefficient ≥104 cm−1, which is make these films suitable for photovoltaic devices. Hall Effect measurement illustrate that all samples have p-type conductivity and the carrier concentration of the thin films was of the order of 1014/cm3