Quantum and transport lifetimes in a tunable low-density AlGaN/GaN two-dimensional electron gas

Journal article

We experimentally determine the density dependence of the transport lifetime (τ t) obtained from low-field Hall measurements and the quantum lifetime (τ q) derived from analysis of the amplitude of Shubnikov-de Haas oscillations in a tunable high mobility two-dimensional electron gas (2DEG) in a Al 0.06Ga 0.94N/GaN heterostructure. Using an insulated gate structure, we are able to tune the 2DEG density from 2 × 10 11 to 2 × 10 12 cm -2, and thus, monitor the evolution of the scattering times in a single sample at T=0.3 K in a previously unexplored density regime. The transport lifetime τ t is a strong function of electron density, increasing from ∼2.7 ps at n e=2 × 10 11 cm -2 to ∼11 ps at n e= 1.75 × 10 12cm -2. Conversely, we find that the quantum scattering time τ q is relatively insensitive to changes in electron density over this range. The data suggest that dislocation scattering accounts for the density dependence of τ q as well as τ t in our low-density sample. © 2004 American Institute of Physics.

Authors: Manfra, M; Simon, S; Baldwin, K; Sergent, A; West, K

• Publication status: Published
• Journal: APPLIED PHYSICS LETTERS
• Volume: 85
• Issue: 22
• Pages: 5278-5280
• Publication date: 2004-11-29
• DOI: 10.1063/1.1827939
• ISSN: 0003-6951
• Language: English