Modelling of bandgap and band offset properties in III-N related heterostructures

Tight binding modelling of electronic band structure in conventional InGaN/GaN and dilute GaAsN/GaAs nitride heterostructures

“…Figure 1 displays the calculated band gaps of conventional InGaN and dilute GaAsN ternary semiconductors plotted as a function of alloy composition. Strain effects on band gaps and band offsets are calculated according to the statistical thermodynamic theory of semiconductors [4][5][6]12]. Excellent agreement is found with measured band gaps [9][10][11] at the Γ, L and X symmetry points of the Brillouin zone for ternary alloys; The band gaps of InGaN increase with composition for 0 < x < 1.…”

“…The on-site and off-site cation and anion atomic energies of a conventional 1 x x A B C -ternary nitride semiconductor such as InGaN is written as [4][5][6] …”

Tight binding modelling of electronic structure of GaPN/GaP, InAsN/InAs and GaAsN/GaAs heterostructures

“…In the framework of 2NN sp 3 s * TB model, the effects of alloy composition and lattice mismatch induced interface strain on electronic band structure of III-V nitrides based heterostructures are calculated by using the so called modified virtual crystal approximation (MVCA) [10][11][12]. The MVCA allows us to take accurately into account the disorder-induced nonlinear variation of the lattice constant and tight binding parameters in calculating the electronic band structure properties such as band gaps, conduction and valence band offsets at interface and in turn the effective masses of charge carriers.…”

“…The effect of composition disorder on TB Hamiltonian matrix elements is then described in terms of the host bond length and the distorted bond length by the substitutional impurity without any adjustable parameter [10][11][12]. Equation (2) can now be used to take into account the composition effects on diagonal and off-diagonal matrix elements of 2NN sp 3 s * TB Hamiltonian, expressed as [10][11][12]:…”

“…Equation (2) can now be used to take into account the composition effects on diagonal and off-diagonal matrix elements of 2NN sp 3 s * TB Hamiltonian, expressed as [10][11][12]:…”