Impact of ZnTe, SbZnTe and SnZnTe absorber materials for multi-layered solar cell: Parametric extraction and layer wise internal analysis

Abstract

In this research paper, Sb and Sn doped Zinc Telluride (ZnTe) thin films are prepared on the glass substrate through low-cost melt-quenching technique. These films are characterized to observe the nature of materials through XRD patterns. Subsequently, these materials are explored as the absorber-layer in the multi-layered solar cell. At 1.5 μm absorber thickness, the current density for SbZnTe and SnZnTe cells is improved by 1.1x and 2.6x respectively, as compared to ZnTe cell. This current density is augmented by 26 % and 31 % when thickness is incremented from 0.5 to 2.5 μm for SbZnTe and SnZnTe layers, respectively. The Fill Factor improves by 5.3 % for SbZnTe and 49 % for SnZnTe than ZnTe cell. Further, these cells are examined through horizontal-cut-line within the absorber layer and vertical-cut-line along the device thickness to explore layer-wise internal processes. Subsequently, potential distribution, Valance/Conduction band energy, charge carrier concentration, hole/electron current density, electric field and recombination rate are analyzed. The holes and electrons concentration are higher by 9.84 % and 8.96 % respectively for SnZnTe than SbZnTe cell. The conversion efficiency of SbZnTe and SnZnTe is achieved as 10.6 % and 17.8 % at 2.5 μm, which is higher by 1.15x and 1.93x in comparison to the ZnTe based solar cell. The SnZnTe cell shows holistic performance owing to its lowest band-gap of 1.39 eV. Moreover, this absorber material leads to highest charge carrier generation, thereby hole and electron current densities are improved by 11.86 % and 35.50 % than the SbZnTe cell.