Lattice-matched InAlN/GaN two-dimensional electron gas with high mobility and sheet carrier density by plasma-assisted molecular beam epitaxy

We report the growth and electron transport studies of two-dimensional electron gases confined at the lattice-matched In0.17Al0.83N/GaN heterostructure on GaN templates by plasma-assisted molecular beam epitaxy. The two-dimensional sheet carrier density, 2.68×1013 cm−2, at room temperature is the manifestation of spontaneous polarization charge differences between the InAlN and the GaN layers. The heterostructure shows the Hall mobilities of 1080 and 3330 cm2/V s at 300 and 20 K, respectively. The variable temperature Hall measurements in the range of 20–300 K reveal that the mobility and sheet carrier density have been nearly independent of temperature below about 150 K, a typical behavior of 2DEG structures. The achievement of high mobility can be attributed to the improvement of InAlN epitaxial growth conditions and reduced alloy disorder scattering of carriers.