Effects of the Growth Temperature on the Properties of CdTe Thin Films for Solar Cell Applications

Abstract

CdTe films for solar cell application were prepared at various growth temperatures by a vacuum evaporation system having close spacing between the source and substrate. The CdTe thin films had a cubic structure highly oriented with the (111) direction perpendicular to the substrate surface, regardless of the growth temperature. The crystallites are of random shape and reach up to about 2 µm in size with increasing growth temperature. The higher growth temperature contributed to the reduction of dark resistivity from 6 × 10 7 ·cm at room temperature to 45.4 × 10 6 ·cm at 300 • C. The photovoltaic properties of the CdS/CdTe solar cell were considerably improved with the increase in the growth temperature, which was caused by the increase of (111) texture and grain size in CdTe films.

Influence of Deposition Conditions on Properties of All Sputtered CdS/CdTe Thin-Film Solar Cells

“…However, the average grain size is smaller at lower growth temperatures. 15 The grain size of the CdTe film deposited at 400 C was about 0.6-0.7 m. This size is comparable to those reported by Uda et al 13 Figure 3 shows the surface morphologies of the CdTe films annealed at 450 C with CdCl 2 post treatment. The grain size in the CdTe films increased due to recrystallization, regardless of substrate temperature.…”

Growth regimes of CdTe deposited by close-spaced sublimation for application in thin film solar cells

“…The influence of the deposition parameters on CdTe-film growth were studied by several groups. Lee [5] found an improvement in texture and electrical properties for increasing substrate temperatures in the very low temperature region (150-300°C). Alamri [6] investigated the correlation between substrate temperature and growth rate, texture and morphology.…”

Structural and Optical Properties of Sputtered Cadmium Telluride Thin Films Deposited on Flexible Substrates for Photovoltaic Applications

“…When polycrystalline materials are under uniform stress, the interplanar spacing changes from a stress-free (power standard) value to a new value corresponding to the magnitude of the applied stress. 9 For the (1 1 1) preferentially oriented thin films, the interplanar spacing of the (1 1 1) Figure 3 shows the interplanar spacing of the (1 1 1) plane, determined accurately using the method developed by Taylor and Sinclair 11 and Nelson and Riley. 12 For sputtering pressures lower than 1.1 Pa, the d 111 was larger than 0.3742 nm (powder standard), indicating that the CdTe films were under compression stress.…”