Predominant Scattering Mechanisms in Quaternary AlInGaN/GaN Heterostructures

Scattering mechanisms that limit the mobility of two-dimensional electron gas (2DEG) in AlInGaN/GaN heterojunctions with three different barrier layer thicknesses of 37.2 (sample A), 10.6 (sample B) and 4.30 (sample C) nm were studied. Hall measurements were performed between 12 and 350 K. Mobilities limited by scattering due to acoustic and optic phonons, dislocation, interface roughness, and alloy disorder were used in the calculation. It was found that scattering, predominantly due to interface roughness, determine the Hall mobility for all samples at different strengths. The highest electron mobility of 492 cm2V-1s-1 at room temperature is obtained for sample B with a high sheet density of about 4.43x1013 cm-2 and a corresponding sheet resistance of 287 Ω/.