TITLE:
Theoretical Analysis of the Effect of the Interfacial MoSe2 Layer in CIGS-Based Solar Cells
AUTHORS:
Adama Sylla, N’Guessan Armel Ignace, Touré Siaka, Jean-Pierre Vilcot
KEYWORDS:
CIGS, Numerical Simulation, AFORS-HET, Quasi-Ohmic Contact, Schottky Contact, MoSe2, Tunnel Layer
JOURNAL NAME:
Open Journal of Modelling and Simulation,
Vol.9 No.4,
August
30,
2021
ABSTRACT: The aim of this work is to analyze the influence of the interfacial MoSe2 layer on the performance of a
/n-ZnO/i-ZnO/n-Zn(O,S)/p-CIGS/p+-MoSe2/Mo/SLG solar cell. In this investigation, the numerical simulation software AFORS-HET is used to calculate the electrical
characteristics of the cell with and without this MoSe2 layer. Different
reported experimental works have highlighted the presence of a thin-film MoSe2 layer at the
CIGS/Mo contact interface. Under a tunneling effect, this MoSe2 layer transforms
the Schottky CIGS/Mo contact nature into a quasi-ohmic one. Owing to a heavily
p-doping, the MoSe2 thin layer allows better transport of majority carrier, tunneling them from
CIGS to Mo. Moreover, the bandgap of MoSe2 is wider than that of the CIGS absorbing layer, such that an electric field is
generated close to the back surface. The presence of this electric field
reduces carrier recombination at the interface. Under these conditions, we
examined the performance of the cell with and without MoSe2 layer. When the
thickness of the CIGS absorber is in the range from 3.5 μm down to 1.5 μm, the
efficiency of the cell with a MoSe2 interfacial layer remains almost constant, about 24.6%, while that of the MoSe2-free
solar cell decreases from 24.6% to 23.4%. Besides, a Schottky barrier height
larger than 0.45 eV severely affects the fill factor and open circuit voltage
of the solar cell with MoSe2 interface layer compared to the MoSe2-free solar cell.