Two-dimensional Janus group-III ternary chalcogenide monolayer compounds B2XY, Al2XY, and BAlX2 (X, Y = S, Se, Te) with high carrier mobilities

First-principles approach based on density functional theory is employed in order to investigate the structural, electronic, and mechanical properties of the two-dimensional Janus group-III ternary chalcogenide monolayer (G3TCM) semiconductor series, B2XY, Al2XY, and BAlX2 (X, Y = S, Se, Te; X not equal Y). The effective masses, band gaps, and carrier mobilities of the entire series of Janus G3TCM compounds are evaluated to comprehensively examine their feasibility as an ingredient in nanoscale electronic device. All the G3TCM compounds proposed in this study are suggested to be realizable based on phonon calculations and estimated mechanical stability. The indirect bandgap of B2XY and Al2XY can be switched to direct bandgap in BAlX2 by constructing Janus-type structure using group-III elements. The computationally obtained carrier mobilities according to the deformation potential theory indicated that B2SSe and BAlSe2 have exceptional electron and hole carrier mobility of 2.02 x 10(4) and 2.58 x 10(5) cm(2) V-1 s(-1), respectively, at room temperature.

Automated summary

The structural, electronic, and mechanical properties of two-dimensional Janus group-III ternary chalcogenide monolayers were investigated using a first-principles approach based on density functional theory. The feasibility of the entire series of compounds as ingredients in nanoscale electronic devices was comprehensively examined, with specific focus on carrier mobilities. The results showed that B2SSe and BAlSe2 have exceptional electron and hole carrier mobility at room temperature.