Integration of n-type and p-type quantum-well infrared photodetectors for sequential multicolor operation

A multicolor infrared photodetector based on the epitaxial integration of an n-type with a p-type GaAs/AlGaAs quantum-well stack is experimentally demonstrated. Additionally, a quantum-well GaAs light-emitting diode is inserted between the stacks to achieve up-conversion of mid-infrared radiation to near-infrared signal. This device shows a remarkable selectivity on wavelength: depending on the bias voltage the peak wavelength detection can be switched on and off between 9.1 and 4.85 μm.