A quantum ring terahertz detector with resonant tunnel barriers

The electronic properties of InAs/GaAs quantum rings and the characteristics of resonant tunnel intersubband terahertz detectors with quantum ring active regions have been studied. The electronic states of the quantum rings have been calculated and measured by the capacitance-voltage technique. The detectors exhibit extremely low dark current density values similar to 5x10(-5), 4.7x10(-2), and 3.5x10(-1) A/cm(2) under a -1 V bias at 4.2, 80, and 300 K, respectively. Three prominent response peaks are observed at similar to 6.5, 10, and 12.5 THz up to T=120 K. At 80 K, the responsivity of the peaks varies from 0.07 to 0.02 A/W.