Contact resistance to high-mobility AlGaAs/GaAs heterostructures
The authors report an investigation of contact resistance to high-mobility 2DEG structures ( approximately 1*106 cm2 V-1 s-1) as a function of temperature (30-300 K) and magnetic field (0-0.6 T). The transmission line model (TLM) and the two-layer TLM of Look (1988, 1989) are used to evaluate to evaluate the contact resistance. The calculated specific contact resistance shows a strong temperature dependence, with both thermionic and tunnelling behaviour. The vestiges of an interface remain below the contact region. Using the two-layer TLM analysis, the degree of parallel conduction in the samples is obtained.