Intermixing in strained InGaAs/GaAs quantum-well infrared photodetectors

The effect of interdiffusion on strained InGaAs/GaAs quantum-well infrared photodetectors is investigated. Photoluminescence measurements of the inter band transition indicate that there is minimal deterioration of the anneale d heterostructures, as it is also evident from both the transverse electric and transverse magnetic infrared intersubband optical transitions. The abs orption peak wavelength is redshifted from the as-grown 10.2 mu m to 10.5 a nd 11.2 mu m for 5 and 10 s annealing, respectively, at 850 degrees C witho ut appreciable degradation in absorption strength. The peak responsivity of the as-grown and annealed spectra is of comparable amplitude, whereas the annealed spectra become narrower in shape. The dark current of the annealed devices is about an order of magnitude higher than the as-grown one at 77 K. (C) 1999 American Institute of Physics. [S0003-6951(99)02508-5].