Energy gap bowing and refractive index spectrum of AlInN and AlGaInN

Abstract

High-quality polycrystalline AlInN films are deposited by low-temperature magnetron reactive sputtering. The energy band gap is measured across the entire compositional range and strong band gap bowing is observed. Within the transparency wavelength region, the effect of AlInN composition on the refractive index spectrum is strongest at shorter wavelength. Taking these measurements into account, non-linear interpolation formulas are employed to predict band gap and refractive index of quaternary AlGaInN for arbitrary compositions.