Enhanced quantum oscillations and scattering effect in quaternary InAlGaN/GaN two-dimensional electron gas

Abstract

Quantum transport properties of a large bandgap In0.15Al0.79Ga0.06N/GaN quaternary GaN high electron mobility transistor (HEMT) heterostructure are studied at low temperatures up to 2 K. Herein, we report the first evidence of weak localization in a quaternary GaN two-dimensional electron gas (2DEG) system. We observe negative magnetoresistance behavior and extracted dephasing time (τΦ) using a Hikami–Larkin–Nagaoka model at 2.2 K. Linear dependency of dephasing rate with temperature (τΦ−1∝T) is established below 20 K. Furthermore, Shubnikov–de Haas quantum oscillation induced by 2DEG is observed using perpendicular magnetic (B⊥) field strengths up to 14 T. From the temperature-dependent oscillation amplitude, we extracted an effective mass m*≈0.237me. The dominance of small-angle scattering in the 2DEG channel is identified from less than unit ratio (τq/τt≪1) of quantum lifetime (τq) to the Hall transport lifetime (τt). In our study, we have demonstrated that the In0.15Al0.79Ga0.06N/GaN quaternary heterostructure possesses high dephasing time (τΦ=5.4 ps) and larger quantum lifetime (τq=0.102 ps) indicating better suitability and a way forward to high-power–high-frequency GaN HEMT development.

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

“…At very low magnetic fields (inset of Figure (a)), the longitudinal resistance exhibits a rapid decrease, attributed to weak localization (WL), a phenomenon commonly observed in disordered semiconductor systems. , As the magnetic field (B) increases, the degeneracy of Landau levels (LL) rises, causing LL to intersect the Fermi level and leading to oscillations in the electronic density of states at the Fermi level. This phenomenon, observed in various electrical properties, is referred to as quantum oscillation . Quantum oscillations in resistance are called Shubnikov-de Haas (SdH) oscillations, whereas in magnetization, they are referred to as de Haas-van Alphen (dHvA) oscillations.…”

“…This phenomenon, observed in various electrical properties, is referred to as quantum oscillation. 24 Quantum oscillations in resistance are called Shubnikov-de Haas (SdH) oscillations, whereas in magnetization, they are referred to as de Haas-van Alphen (dHvA) oscillations. Increasing B enhances the prominence of SdH oscillations in our InAlN/GaN sample, SdH oscillations were observed above a critical magnetic field value of 5 T. The magnetoresistance (MR) exhibited a parabolic behavior within the intermediate magnetic field range (1.5T to 4T), as illustrated in Figure 5(b).…”

“…Transport properties serve as a crucial tool to understand the scattering mechanisms in the two-dimensional electron gas (2DEG) channel effectively. Various characterization techniques have been employed to ensure the production of high-quality samples. − Magnetoresistance measurements in quantum transport serve as a powerful tool for characterizing compound semiconductors, facilitating a deeper understanding of their electronic properties. − Quantum oscillations and their scattering phenomena have been extensively explored in various GaN based heterostructures. ,,− However, the quantum transport behaviors in this high-mobility InAlN/GaN heterostructure have not been widely reported. In particular, study on the InAlN/GaN 2DEG systems with high mobility remains a long-standing challenge due to growth challenges.…”