Investigation on the photocatalytic properties of SiI2/InSe and SiI2/InTe heterojunctions

Abstract

The electrical, optical and photocatalytic properties of SiI₂/InSe and SiI₂/InTe heterojunctions have been investigated based on the energetic, thermodynamic and mechanically stability assessment. The tuning effects of band gap incurred by applied strain and electric field have also been explored. The results indicated that the constructed heterojunctions are type–II heterojunctions with Z–alignment and showing narrow band–gap values of 1.4769 eV and 1.8335 eV respectively. The lower exciton binding energy coupled with the higher mobility of electrons as well as stronger light absorption coefficient make the STH of them can be achieved to 24.31 % and 18.01 % respectively. The STH of SiI₂/InSe can be increased from 24.31 % to 30.23 % with compressive strain while that of SiI₂/InTe is increased from 18.01 % to 38.16 % with tensile strain. The HER and the OER analysis indicates HER will take place on SiI₂ side for the SiI₂/InSe heterojunction, while it takes place on the InTe layer for the SiI₂/InTe. The HER and OER reaction can happen spontaneously by adjusting U_e and pH moderately or driven via an applied bias potential due to acidic environment is not conducive to the HER and OER.