Structural, optoelectronic and photocatalytic properties of MX (M=Ga, In; X=S, Se, Te) contact with novel janus GaInS3 monolayers

Abstract

Using DFT calculations, we have fabricated the MX-GaInS3 (M = Ga, In; X = S, Se, Te) van dar Waals Heterostructures (vdWHs) and systematically calculated the structural, electronic, optical and photocatalytic properties. The calculated binding energies and AIMD simulations confirm the robust evidence for the stability of MX-GaInS3 vdWHs. Despite of the indirect bandgap nature of MX (M = Ga, In; X = S, Se, Te) monolayer, interestingally MX-GaInS3 vdWHs are direct bandgap semiconductors with type-II band alignments. Charge density difference, bader charges and the average electrostatic potential are calculated to investigate the transfer of charges amoung the layers at the interface of MX-GaInS3 vdWHs. Using dispersion along high symmetry path by fitting the band edges, we have also calculated the effective mass of carriers in MX-GaInS3 vdWHs. Smaller effective mass with higher mobility of carrier, suggest MX-GaInS3 vdWHs best candidate for optoelectronic devices. Absorption spectra in term of ε2(ω) of MX-GaInS3 (M = Ga, In; X = S, Se, Te) vdWHs are also calculated and investigated in detail. Both the conduction and valence band edges in GaS-GaInS3 vdWHs straddle the standard redox band edge potentials, hence have the ability to perform both reduction and oxidation, confirming the potentiality for full water splitting at pH = 0.