Quantum transport in neutron-irradiated modulation-doped heterojunctions. II. Thermal neutrons

We have investigated the characteristics of the low-temperature quantum transport Al_xGa_1-xAs/GaAs modulation-doped heterojunctions irradiated by thermal neutrons of about 0.025 eV energy. Time-dependent effects related to nuclear radiation such as β^- decay and γ radiation are discussed in detail. The concentration and the mobility of the two-dimensional electron gas (2D EG) under low magnetic fields, the Hall plateau broadening, and the Shubnikov–de Haas (SdH) oscillation enhancement under strong magnetic fields all increase immediately after the irradiation, and then relax for long times. Above all, parallel conduction without illumination is first observed by us with a higher flux of thermal neutrons.