Rights Creative Commons: Attribution 3.0 Hong Kong License Impurity free intermixing InGaAs/GaAs strained multiple quantum well infrared photodetector

Interdiffusion effect has been investigated in highly strained InGaAs/GaAs multiple quantum well (MQW) infrared photodetector. Impurity-free interdiffusion techniques (IFVD) was utilized via rapid thermal annealing (RTA) using electron-beam evaporated Si02 cap layers at temperature 850 °C to study the optical and electrical properties of the interdiffused photodetector. Photoluminescence (PL) spectrum is blue shifted and PL linewidth remains almost the same, indicating no strain relaxation and deterioration of the heterostructure quality. Both transverse magnetic and transverse electric infrared intersubband transitions are retained and observed after intermixing. The absorption peak wavelength is red shifted continuously from the as grown 10.20 to the interdiffused 10.5 and 1 1.17 jim, respectively, without appreciable degradation in absorption strength for 5 and 10 s annealing. Annealed responsivity spectra of both O and 900 polarization are of compatible amplitude and red shifted but with narrower spectra linewidth. Dark current of the annealed devices is found to be an order of magnitude larger than the as-grown one at 77K