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 ( τ Φ ) using a Hikami-Larkin-Nagaoka model at 2.2 K. Linear dependency of dephasing rate with temperature ( τ Φ− 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 * ≈ 0.237 m e . The dominance of small-angle scattering in the 2DEG channel is identified from less than unit ratio ( τ q / τ t ≪ 1 ) of quantum lifetime ( τ q ) to the Hall transport lifetime ( τ t ) . In our study, we have demonstrated that the In0.15Al0.79Ga0.06N/GaN quaternary heterostructure possesses high dephasing time ( τ Φ = 5.4 ps ) and larger quantum lifetime ( τ q = 0.102 ps ) indicating better suitability and a way forward to high-power-high-frequency GaN HEMT development.