Energy-band gap of monolayer superlattices calculated by a modified tight-binding method with electronegativity

The tight-binding method is modified successfully to calculate the energy-band gap at the \ensuremath{\Gamma} point for monolayer superlattices in which each monolayer comprises a binary and ternary compound semiconductor. In the case of (InAs${)}_{1}$/(GaAs${)}_{1}$ monolayer superlattices, the energy-band gap is 5% smaller than that of ${\mathrm{In}}_{0.5}$${\mathrm{Ga}}_{0.5}$As ternary compound semiconductors. The energy-band gap of (InAs${)}_{1}$/(GaAs${)}_{1}$ monolayer superlattices increases nonlinearly to that of the ternary compound semiconductors as the degree of alloying between In and Ga atoms is increased.