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

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 (tau(Phi)) using a Hikami-Larkin-Nagaoka model at 2.2 K. Linear dependency of dephasing rate with temperature (tau(-1)(Phi) proportional to T) is established below 20 K. Furthermore, Shubnikov-de Haas quantum oscillation induced by 2DEG is observed using perpendicular magnetic (B-perpendicular to) field strengths up to 14 T. From the temperature-dependent oscillation amplitude, we extracted an effective mass m* approximate to 0.237m(e). The dominance of small-angle scattering in the 2DEG channel is identified from less than unit ratio (tau(q)/tau(t) << 1) of quantum lifetime (tau(q)) to the Hall transport lifetime (tau(t)). In our study, we have demonstrated that the In0.15Al0.79Ga0.06N/GaN quaternary heterostructure possesses high dephasing time (tau(Phi) = 5.4 ps) and larger quantum lifetime (tau(q) = 0.102 ps) indicating better suitability and a way forward to high-power-high-frequency GaN HEMT development.

Automated summary

In this study, weak localization and negative magnetoresistance behavior are observed in a quaternary GaN two-dimensional electron gas (2DEG) system. The dephasing time and temperature dependency of the dephasing rate are determined using a Hikami-Larkin-Nagaoka model. Shubnikov-de Haas quantum oscillation induced by 2DEG is also observed.