Ojo, A.; Dharmadasa, I. Factors Affecting Electroplated Semiconductor Material Properties: The Case Study of Deposition Temperature on Cadmium Telluride. Coatings2019, 9, 370.
Ojo, A.; Dharmadasa, I. Factors Affecting Electroplated Semiconductor Material Properties: The Case Study of Deposition Temperature on Cadmium Telluride. Coatings 2019, 9, 370.
Ojo, A.; Dharmadasa, I. Factors Affecting Electroplated Semiconductor Material Properties: The Case Study of Deposition Temperature on Cadmium Telluride. Coatings2019, 9, 370.
Ojo, A.; Dharmadasa, I. Factors Affecting Electroplated Semiconductor Material Properties: The Case Study of Deposition Temperature on Cadmium Telluride. Coatings 2019, 9, 370.
Abstract
Electrodeposition of cadmium telluride (CdTe) on fluorine doped tin oxide (FTO) using two electrode configuration was successfully achieved with the main focus on the growth temperature. The electroplating temperatures explored ranges between (55 and 85)℃ for aqueous electrolytes containing 1.5 M cadmium nitrate tetrahydrate (Cd(NO3)2 •4H2O) and 0.002 M tellurium oxide (TeO2). The ensuing CdTe thin-films were characterised using X-ray diffraction (XRD), UV-Vis spectrophotometry, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and photoelectrochemical (PEC) cell measurements. The electroplated CdTe thin-films exhibit a dominant (111) CdTe cubic structure, while the crystallite size increases with the increase in the electroplating temperature. The internal strain, dislocation density and the number of crystallites per unit area decrease with increasing growth temperature. The optical characterization depicts that the CdTe samples show comparable absorbance and a resulting bandgap of 1.51±0.03 eV for as-deposited CdTe layers. A marginal increase in the bandgap and reduction in the absorption edge slope towards lower deposition temperatures were also revealed. The annealed CdTe thin-films showed improvement in energy bandgap as it tends towards 1.45 eV while retaining the aforementioned absorption edge slope trend. Scanning electron microscopy shows that the underlying FTO layers are well covered with increasing grain size observable relative to the increase in the deposition temperature. The energy dispersive X-ray analyses show an alteration in the Te/Cd relative to the deposition temperature. Higher Te ratio with respect to Cd was revealed at deposition temperature lower than 85℃. The photoelectrochemical cell study shows that both p- and n-type CdTe can be electroplated and that deposition temperatures below 85℃ at 1400 mV results in p-type CdTe layers.
Keywords
Electrodeposition; CdTe film; Two-electrode configuration; thin films, electroplating temperature
Subject
Chemistry and Materials Science, Surfaces, Coatings and Films
Copyright:
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