SCAPS Modeling for Degradation of Ultrathin CdTe Films: Materials Interdiffusion

Abstract

Ultrathin film solar cells based on CdS/CdTe (d CdTe £ 1 lm) suffer from two main issues: incomplete photo absorption and high degradation rate. The former is cured by light-trapping techniques, whereas the latter is a matter of fabrication details. Interdiffusion of the material components and formation of subsequent interlayers at the front/back region can change the optical/electrical properties and performance/stability of the device. We model the degradation of the ultrathin CdTe film devices considering the material interdiffusion and interlayers formation: CdTeS, CdZnTe, Cu x Te (i.e., Te/Cu bilayer), and oxide interlayers (i.e., CdTeO 3 ). The diffusion rate of the materials is considered separately and the reactions that change the interlayer's properties are studied. Additionally, a back contact of single-walled carbon nanotube showed a higher stability than the metallic contacts. A new time-dependent approach is applied to simulate the degradation rate due to formation of any interlayer. It is shown that the materials interdiffusion causes a defect increment under thermal stress and illumination. The metallic back contact accelerates the degradation, whereas single-walled carbon nanotubes show the highest stability. A SCAPS simulator was used because of its ability in defining the properties of the back contact and metastabilities at the interface layers. The properties of the layers were taken from the experimental data reported in the literature.

Role of contact work function, back surface field, and conduction band offset in Cu2ZnSnS4 solar cell

“…Most of them (SCAPS, AMPS, PC1D, GPVDM) solves 1D Poisson and continuity equation for hetero-structures. We used the solar cell capacitance simulator SCAPS-1D version 3.0.2 [46][47][48][49][50][51] Initially, a benchmarking is done via incorporation of a suitable defect model to match the simulation results of the baseline solar cell configuration with the corresponding experimentally reported values of Shin et.al. [22] We have chosen Shin et.al.…”

Investigation of Electrical Parameters of CdTe Photovoltaic Devices by Computational Analysis

“…So, to reduce the defect density in this region, S/Te concentration should be increased so that grain size of particles could become more smooth in this region. [ 58,66 ] Hence, to achieve better performance of electrical parameters of CdTe photovoltaic cell, a defect of 1 × 10 14 cm −3 should be maintained. Compared to other sources, this result is very similar to previous reported results.…”

The Impact of Graphene on the Fabrication of Thin Film Solar Cells: Current Status and Future Prospects

“…This group also claimed that the dangling bonds between graphene networks might generate movable ions, especially with the co-existence of metal dopant. Those free ions would diffuse into the p-n junction interface, and, therefore, cause damage to the device rather than at the back contact interface [ 45 ]. In addition, several reports related to the application of single-wall carbon nanotube were also indicated with a better device efficiency up to 14.1% [ 46 ].…”