Experimental and Numerical Simulation of Molybdenum Oxide Films with Wide Bandgap and High Work Function for Carrier-Selective Contact Solar Cells

Abstract

In silicon heterojunction (SHJ) solar cells, a wide bandgap material with a high work function is widely used as the hole extraction pathway to attain high efficiency. We introduced a molybdenum oxide (MoOx) film as an effective hole-transfer layer in carrier selective contact (CSC) solar cells by virtue of its wide bandgap along with high work function. The passivation characteristics, optical and electrical properties of MoOx films were investigated by differing thickness and work function. The combination of 6 nm hydrogenated intrinsic amorphous silicon (a-Si:H(i)) and 7 nm thermally evaporated MoOx passivation layers provides excellent passivation properties, reduces carrier recombination, and improves the cell performance. The synthesized CSC solar cells showed promising results, with an open-circuit voltage (Voc) of 708 mV, short-circuit current (Jsc) = 37.38 mA cm−2, fill factor (FF) = 74.59%, and efficiency (η) = 19.75%. To justify the obtained result, an AFORS HET simulation was conducted based on the experimental results. The high work function and wide bandgap MoOx/c-Si(n) interface developed a considerable built-in potential and suppressed the electron–hole pair recombination mechanism. The CSC solar cell’s simulated performance was enhanced from 1.62 to 23.32% by varying the MoOx work function (ΦMoOx) from 4.5 to 5.7 eV.