Fabrication and characterization of improved p-GaTe/n-InSe heterojunction solar cells

InSe thin films were deposited by thermal evaporation of polycrystalline InSe onto the sulfur passivated p-GaTe:In substrates at 450K-550K to fabricate improved p-GaTe:In/n-InSe heterojunction solar cells. Dark J-V measurements showed that the reverse saturation current density decreased from 4 × 10^-6 A/cm² to 2 × 10^-9 A/cm² and the ideality factor was reduced from 2.04 to 1.12 as a result of surface passivation of p-GaTe substrate materials. Under illumination of 75 mW/cm², the open-circuit voltage increased from 0.53 V to 0.62 V and short-circuit current density increased from 7.93 mA/cm² to 10.34 mA/cm² for solar cells with surface passivated p-GaTe:In substrates, leading to an increased solar cell efficiency of ~6.09%.