Influence of deposition temperature in the fabrication of CdTe thin films using RF magnetron sputtering

Abstract

CdTe-based thin film solar cells have shown strong potentials as viable thin film solar cells for the future, due to several attractive material properties. Its direct bandgap, strong absorption coefficient, ease and multiple deposition methods have favored this material in solar cell research and manufacturing. However, the quality of these thin films, depend on the method and process of fabrication. Among the important issues considered for cheaper and more efficient solar cells is the deposition temperature. In this work, CdTe thin films were deposited on glass using RF magnetron sputtering at various temperatures and their structural, optical and electrical characteristics analyzed using SEM, AFM, XRD, and UV-Vis. Results show that grains sizes are not significantly affected for films deposited at 350oC and below. At 400oC however, the grains show remarkable increase in size, while crystallinity is increased with higher deposition temperature. The energy bandgap show gradual increase with temperature, ranging from 1.43–1.54 eV. Overall, this work show that higher deposition temperature is desirable in the fabrication of good quality CdTe films for solar cell applications.