Opto-electronic transport properties of resonant tunneling diodes with type-I and II postwells

We investigate the opto-electronic transport properties of AlGaAs/GaAs double-barrier resonant tunneling diodes (RTDs) with GaAs1−xSbx type-II postwells and compare these to RTDs with InxGa1−xAs type-I postwells. Samples grown with Sb containing type-II postwells show a significant photocurrent enhancement for x = 24% compared to 5.5% and 34%, respectively, which is attributed to an efficient hole trapping based on the large hole trapping barrier of 396 meV. By contrasting the RTDs with type-I InGaAs quantum well RTDs, we observe an increased photoresponsivity by one order of magnitude. Our finding allows realizing RTD with efficient hole trapping in the vicinity of the active region of the double barrier structure with confinement energies well above the thermal energy at room temperature, which may allow the observation of single charge configurations even at elevated temperatures.