The quantum dot spectrometer

We describe the simulations and experiments on an electrically-tunable spectrally-sensitive photodetector based on inhomogeneous absorption in a self-assembled quantum dot array and resonant tunneling through a coupled quantum well layer. The basic structure of our device, the quantum dot spectrometer (QDS) is given. The key components are the quantum dot layer, which produces spectrally sensitive absorption and the coupling layer, which reads out spectral information as a function of the applied voltage, V. The coupling layer consists of a pair of coupled quantum wells. For certain applied bias voltages across the quantum wells, resonant transfer from the quantum dot layer to the collector layer occurs. We have constructed a preliminary device based on these concepts using the InAs-GaAs-AlAs material system.