Electrodeposition of ternary compounds for novel PV application and optimisation of electrodeposited CdMnTe thin-films

Abstract

Growth of polycrystalline CdMnTe ternary compound thin films has been carried out using cathodic electrodeposition technique at different cathodic potentials. The range of the cathodic potentials used in this work has been chosen according to the cyclic voltammogram results. The CdMnTe thin films were electroplated from electrolyte containing CdSO4, TeO2 and MnSO4 in an acidic aqueous medium. Glass/fluorine-doped tin oxide (FTO) substrates have been used to electrodeposit the semiconductor layers. The structural, compositional, morphological, optical and electrical properties of the CdMnTe thin films were studied using X-ray diffraction (XRD), Sputtered neutral-mass spectroscopy (SNMS), Scanning electron microscopy (SEM), UV–Vis spectroscopy and Photo-electro-chemical (PEC) cell measurements respectively. The primarily grown as-deposited (AD) layers went through two different post-growth surface treatment conditions- heat-treated in air in the presence of CdCl2 (CCT) and heat-treated in air in the presence of GaCl3 (GCT). Results from the XRD indicated the polycrystalline nature of the electrodeposited films. The electroplated films have cubic crystal structures and the preferred orientation was found to be along the (111) plane of CdMnTe. Inclusion of Mn has been qualitatively observed using SNMS measurement. The optical energy bandgaps of the thin films were found to be varying between ~ 1.90 and ~ 2.20 eV. Though all the layers after post-treatment showed p-type electrical conduction, both p and n-type conductivity were obtained at different cathodic potentials for as-deposited materials. Comparison of the deposited layers to other electrodeposited ternary compounds has also been discussed.

Property enhancement of a close-spaced sublimated CdTe thin film by a post-growth activation step with CdCl2 and MgCl2

“…The introduction of both these features occurs during the CdCl 2 treatment of ED-CdTe, leading to a significant impact. 41 On the other hand, massive crystals in the mm-scale have already been created using high-temperature grown CSS-CdTe. 40 So, the addition or enhancement has a relatively smaller impact there.…”

How to Achieve Efficiencies beyond 22.1% for CdTe-Based Thin-Film Solar Cells

“…To develop low-cost devices using electroplating, it is essential to develop p-type window materials first. While current efforts are focused on this line [42,43], initial graded band gap devices have been attempted on the already available n-type window materials. Figure 13 shows one such device.…”

“…Figure 15. Main features (a,b) and basic fabrication steps (c) required for a good PV active device.Both electrical contacts are ohmic contacts, and any light-absorbing material or device structure can be incorporated so that the slope of the device structure (internal electric field) is strong[42,43].Summary of Section 3 (i). Because of the higher vapour pressure of Te, CSS-CdTe is intrinsicallyTe-rich, is p-type in electrical conduction and produces comparatively lower efficiencies.…”

Influence of growth time on the properties of CdTe thin films grown by electrodeposition using acetate precursor for solar energy application

“…, and cadmium sulphate (CdSO 4 ) [27]. The structure, morphology, and optical properties of these films are governed by optimization of deposition parameters such as precursor concentrations and ratios of precursor concentrations used to prepare the bath electrolyte, pH of the solution, deposition temperature, cathodic deposition voltage, rate of stirring of the electrolyte, electrodes used, and deposition period.…”

“…For solar cell device applications, the absorbance of the layer depends on the film thickness which is significantly controlled by deposition time [28]. In the case of CdTe, its thin film has a high absorption coefficient, and to absorb up to 99% of the visible part of solar spectra, about 2 μm thickness is required [27]. In the development of high-efficiency CdTe-based thin film solar cells, the reduction of the thickness of the CdS window/buffer layer for minimizing absorption loss, the modification of conductive glass fluorine doped tin oxide (FTO), indium doped tin oxide (ITO), etc.…”