Enhanced Shubnikov–de Haas Oscillations in High Mobility InAlN/GaN Two-Dimensional Electron Gas

Abstract

A high-quality In 0.17 Al 0.83 N/GaN heterostructure with a record high mobility of 11370 cm 2 V −1 s −1 is achieved at 2 K using the metal oxide chemical vapor deposition (MOCVD) technique, where enhanced Shubnikov−de Haas (SdH) oscillations of two-dimensional electron gas (2DEG) are observed at low temperatures up to 20 K. In this study, we explore the quantum transport properties induced by 2DEG using perpendicular magnetic (B ⊥ ) field strengths up to 14 T. Excellent crystalline and structural quality of the ultrathin InAlN/GaN heterostructure was revealed by high resolution X-ray diffraction (HRXRD) and high-angle annular dark-field (HAADF) scanning transmission electron microscopy (STEM). From the temperature-dependent oscillation amplitude, we have derived effective mass m* ≈ 0.247m e . Furthermore, the dominance of small-angle scattering in the 2DEG channel is evidenced by a quantum lifetime (τ q ) to Hall transport lifetime (τ t ) ratio of less than unity (τ q /τ t ≪ 1). These findings offer a robust foundation for exploration into fundamental physics and emergent phenomena in quantum transport within the InAlN/GaN 2DEG, leading to better suitability and a way forward to high power−high frequency GaN high electron mobility transistor (HEMT) development.