The effect of electrons and phonons scattering from interface roughness and well-width fluctuations on low-field mobility of 2DEG in GaN/AlGaN

The influence of interface roughness on the mobility of two-dimensional electrons in GaN/AlGaN HEMT structures are theoretically investigated in light of the measured mobility. Experimental mobility of View the MathML source at View the MathML source, remains almost constant up to lattice temperature View the MathML source. It then decreases rapidly down to View the MathML source at View the MathML source. In order to compare the experimental results with the theory we use a simple analytical formula for low-field electron mobility that uses the two-dimensional degenerate statistics for a 2DEG confined in a triangular well. Interface-roughness scattering dominates the low-temperature mobility of two-dimensional electrons in GaN/AlGaN structures with a high electron density View the MathML source. From comparison between theory and experiment, the correlation length (Λ) and lateral size (Δ) of roughness for GaN /AlGaN 2DEG are estimated. The effect of phonons scattering from interface roughness and well-width fluctuations on low-field mobility of 2DEG in GaN/AlGaN is also investigated.