Study the Structural/Microstructural and Electrical Properties of CdTe:Sb Thin Films Deposited by Flash Evaporation

Abstract

Abstract in this research studied the structure and electrical properties of the Pure CdTe and metal Sb-doped CdTe thin films with 0.5, 1, and 1.5  wt.%, respectively. They deposited on glass substrates using flash evaporation technique. It was found that the prepared films had a cubic structure and a strong preferred <111> crystal orientation. Atomic force microscopy (AFM) results showed that the film surface doped Sb was more compact and uniform and also the root mean squared (RMS) roughness increased with Sb contents. The electrical properties were investigated as function of Sb wt.% doping. The results showed that the electrical conductivity (σ) increasing trend with increasing the wt.% of dopant , while the activation energies (Ea1, Ea2) showed an opposite trend, where the activation energies decreased with dopant.1.Introduction Thin films of II–VI semiconductors are widely used in many semiconductor devices such as photo electrochemical cells, field effect transistors, IR detectors, photodiodes, photo conductors and photovoltaic solar cells[1, 2]. CdTe has long been identified as a candidate for the absorber layer in low cost thin film photovoltaic solar cells because of its direct bandgap, high absorption coefficient and the possibility of a variety of preparation techniques such as close spaced sublimation (CSS)[3], vacuum deposition [4], electrodeposition [5], and RF sputtering[6], close spaced vapor transport [7]. In this present work we focused attention on the prominent techniques for the deposition of thin films of multicomponent alloys whose constituents have different vapor pressures. Thin films of CdTe have been prepared under suitable growth conditions by a simple flash evaporation (FE) technique. This technique requires only one boat maintained at sufficiently high temperature to evaporate the least volatile component of the alloy. The main advantage of (FE) is that it does not require maintaining the critical vapor pressures of the components and temperatures of the boats unlike multisource thermal evaporation[8] . CdTe thin film still has many defects, such as it has extremely high resistivity. To solve this issue, the implying of the technique Sb-doped CdTe film to change electrical properties [9]. In this work deposited Sb-doped CdTe films using the mixed powder of