Interdiffused InGaAs/GaAs strained multiple quantum well infrared photodetector

The effect of interdiffusion on strained InGaAs/GaAs quantum well infrared photodetector is investigated. Transverse magnetic and transverse electric infrared intersubband transitions are observed after interdiffusion. The absorption peak wavelength is red shifted from the as grown 10.20 to the interdiffused 10.5 and 11.17 μm, for 5 and 10 s annealing at 850°C respectively, without appreciable degradation in absorption strength. Responsivity spectra of both 0° and 90° polarization are of compatible amplitude and the shape of the annealed spectra becomes narrower. Dark current of the annealed devices is found to be an order of magnitude larger than the as-grown one at 77 K.