Growth temperature-dependent properties of electrodeposited CdSe thin films for optoelectronic application

Abstract Cadmium selenide (CdSe) thin films were synthesized using a two-electrode electrodeposition technique in potentiostatic mode. The solution matrix contains 0.3 M Cd(NO 3 ) 2 .4H 2 O and 0.03 M SeO 2 on conductive glass substrates/fluorine-doped tin oxide (FTO). The electrodeposited CdSe thin films were examined at various growth temperatures of 55, 65, and 85 °C, both as-deposited (AD) and annealed (HT) samples. A polycrystalline cubic structure of the prepared CdSe thin films was identified using x-ray powder diffraction. The energy bandgap of films was found to vary with deposition temperature and was recorded as 1.85, 2.00, and 2.13 eV for AD and 1.86, 2.16 and 2.70 eV for HT samples deposited at 55, 65, and 85 °C, respectively. Surface morphology images show that the form and grain size varied with growth temperature. The average surface roughness varied with deposition temperature. The elemental analysis confirmed that the proportion of cadmium (Cd) increased while that of Se decreased as the deposition temperature increased for both AD and HT films. The film that was deposited at low temperature (55 °C) can be as a layer for absorption. Conversely, however the film deposited at a high growth temperature (85 °C) is capable of serving as a buffer layer in thin-film solar cell technology.