Temperature Limitations of Quantum Hall Far-Infrared Photodetectors

We have investigated the temperature, T, dependence of a highly sensitive far-infrared (FIR) photodetector fabricated on a two-dimensional electron gas system in GaAs/AlGaAs heterostructures. The photoinduced resistance change, Delta R(xx), observed in different integer quantum Hall (QH) regimes shows different T dependences. At high T, Delta R(xx) is limited by the vanishing of rising electronic temperature Delta T(e). For T < 5 K, Delta R(xx) can either rapidly increase with lower T or slowly diminish, determined by the interplay between the magnetic field dependence of Delta T(e) and the T dependence of QH states. (C) 2010 The Japan Society of Applied Physics