Nearly lattice-matched InAlN/AlGaN two-dimensional electron gas heterostructures grown by metalorganic chemical vapor deposition

Nearly lattice-matched InAlN/Al x Ga 1− x N ( x = 0.1, 0.21, and 0.34) heterostructures with a 1-nm-thick AlN interfacial layer were grown on AlN/sapphire templates by metalorganic chemical vapor deposition. Capacitance–voltage and Hall effect measurements revealed that two-dimensional electron gases (2DEGs) with high densities exceeding 2 × 10 13 /cm 2 were generated at the heterointerface for all samples. It was confirmed that the generation of high-density 2DEGs can be explained as being due to internal polarization effects. The sheet resistance increased from 1,267 to 1,919 Ω/sq with the increase in Al content in the AlGaN channel, owing to the decreases in 2DEG density and mobility.