Analysis of electrodeposited CdTe thin films grown using cadmium chloride precursor for applications in solar cells

摘要

Deposition of cadmium telluride (CdTe) from cadmium chloride (CdCl_2) and tellurium oxide has been achieved by electroplating technique using two-electrode configuration. Cyclic voltammetry shows that near-stoichiometric CdTe is achievable between 1330 and 1400 mV deposition voltage range. The layers grown were characterised using X-ray diffraction (XRD), UV-Visible spectrophotometry, scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), photoelectrochemical (PEC) cell and DC conductivity measurements. The XRD shows that the electrodeposited CdTe layer is polycrystalline in nature. The UV-Visible spectrophotometry shows that the bandgap of both as-deposited and heat-treated CdTe films are in the range of (1.44-1.46) eV. The SEM shows grain growth after CdCl_2 treatment, while, the EDX shows the effect of growth voltage on the atomic composition of CdTe layers. The PEC results show that both p- and n-type CdTe can be electrodeposited and the DC conductivity reveals that the high resistivity is at the inversion growth voltage (V_i) for the as-deposited and CdCl_2 treated layers.