Effect of p-type transition metal dichalcogenide molybdenum ditelluride (p-MoTe2) layer formation in Cadmium Telluride solar cells from numerical analysis

In this paper, we have investigated the effects of transition metal dichalcogenide namely Molybdenum ditelluride (MoTe₂) layer formation in between Cadmium Telluride (CdTe) absorber layer and Mo back contact from numerical modeling. The main purpose was to investigate the possible effects of p-type MoTe₂ in CdTe thin film solar cell. Energy band line-up in the vicinity of Mo/MoTe₂/CdTe interface is investigated to explain the interface properties in terms of various parameters. It was found that p-type MoTe₂ has some effects to the performance of CdTe thin film solar cells. Thickness, bandgap energy and carrier concentration of p-MoTe₂ all have been varied in the numerical simulation to observe its effects on the cell performance. It was found that when thickness of MoTe₂ is less than 20 nm, the cell efficiency decreases, which may be due to the shunting caused by the thinner p-MoTe₂. Furthermore, the increase in MoTe₂ bandgap results in unfavorable effect to the performance of the cell mainly due to the possibility of electrons to drift towards the back contact and recombination. The increase of the carrier concentration improves the cell performance. This could be attributed to the less recombination of electrons as well as less built in potential (V_bi) at MoTe₂/CdTe junction.