A Tight-Binding Based Analysis of the Band Anti-Crossing Model and Its Application in Ga(In)NAs Alloys

This chapter reviews some of the insights gained using the tight-binding method to analyze the band anti-crossing (BAC) model, and its application to describe the electronic structure of GaInNAs and related alloys. Using the tight-binding method, it is confirmed that N forms a resonant state above the Conduction Band Edge (CBE) in Ga(In)As, and that the interaction of the N resonant states with the CBE accounts for the strong band gap bowing observed in Ga(In)As. It is explicitly demonstrated that the alloy CBE (often referred to as the E_ level) can be described very accurately by the BAC model, in which the nitrogen levels are treated explicitly using a Linear Combination of Isolated Nitrogen Resonant States (LCINS). This analytical model provides a consistent fit to the ground and excited state transition energies measured across a wide range of samples. The model can be readily applied to describe any GalnNAs-based QW structures. Turning to the conduction band dispersion, showed that the two-level BAC model must be modified to give a quantitative understanding of measured electron mass values. It is concluded that the methods and insights presented in the chapter provide a strong base for further investigation and analysis of fundamental properties and also because of its potential device applications.