Photocurrent spectra of very long wavelength GaAs/AlGaAs quantum well infrared photodetector

The photocurrent spectra characteristics of the 15 mum very long wavelength GaAs/AlGaAs quantum well infrared photo detector(QWIP) have been investigated. The two photocurrent response peaks, which have a Gaussian lineshape due to the random fluctuation of the well width, are attributed to the transitions from the ground state E-0 to the first excited state E-1 and the third excited state E-3 in the well, respectively. The transition peaks shift linearly to higher energy as the bias across the detector increases. Taking into account electrons exchange effect, we find that the theoretical calculation using the transfer matrix method agrees well with the experimental data.