  Inorganic CdTe and FeSi2-based solar cells have recently drawn a lot of
attention because they offer superior thermal stability and good optoelectronic
properties compared to conventional solar cells. In this work, a unique
alternative technique is presented by using FeSi2 as a secondary absorber layer
and In2S3 as the window layer for improving photovoltaic (PV) performance
parameters. Simulating on SCAPS-1D, the proposed double-absorber
(Cu/FTO/In2S3/CdTe/FeSi2/Ni) structure is thoroughly examined and analyzed. The
window layer thickness, absorber layer thickness, acceptor density (NA), donor
density (ND), defect density (Nt), series resistance (RS), and shunt resistance
(Rsh) were simulated in detail for optimization of the above configuration to
improve PV performance. According to this study, 0.5 um is the optimized
thickness for both the CdTe and FeSi2 absorber layers in order to maximize
efficiency. Here, the value of the optimum window layer thickness is 50 nm. For
using CdTe as a single absorber, the efficiency is achieved by 13.26%. But for
using CdTe and FeSi2 as a dual absorber, the efficiency is enhanced and the
obtaining value is 27.35%. The other parameters are also improved and the
obtaining values for fill factor (FF) are 83.68%, open-circuit voltage (Voc) is
0.6566V, and short circuit current density (JSc) is 49.78 mA/cm2. Furthermore,
the proposed model performs good at 300 K operating temperature. The addition
of the FeSi2 layer to the cell structure has resulted in a significant quantum
efficiency (QE) enhancement because of the rise in solar spectrum absorption at
longer wavelengths. The findings of this work offer a promising approach for
producing high-performance and reasonably priced CdTe-based solar cells.
