Forward bias voltage controlled infrared photodetection and electroluminescence from a p-i-n quantum dot structure

We report a specially designed p-i-n quantum dot (QD) device in which both the intersubband and the interband transitions of the QD are controlled by the applied forward bias voltage. The design is achieved by using asymmetric AlGaAs barriers on both sides of only one QD layer and by placing two-dimensional electron gas structure on one side of the QD layer. Experimentally, at 77 K, the device can detect normal incidence infrared light of about 5.6 µm when the forward bias voltage is in between about 3 and 7 V, while it emits electroluminescence of about 1 μm when the applied forward bias voltage is larger than 11 V.