Opto-electronic characterization of InAs/GaSb superlattice photodiodes operating in the mid-wavelength infrared

In this thesis, opto-electronic characterization of InAs/GaSb superlattice photodiodes operating in mid-infrared region have been studied. Doping calibration for InAs and GaSb materials have been completed by using Hall effect measurements. The change in the carrier type as a function of temperature in unintentionally doped superlattices has been investigated as well by using the same technique. The change in the cut-off wavelength and the transitions between the energy levels have been investigated by using the spectral photoresponse and absorption measurements for the superlattice structures where the individual layer thicknesses were systematically changed. The band edge tuning and their ability for high temperature operation have been examined by temperature dependent optical measurements. Photo-current generation in the photodiodes have also been investigated by responsivity measurements and their quantum efficiencies were calculated. Temperature dependent dark current measurements showed that the generation-recombination (G-R) and surface leakage currents are dominant mechanisms at different temperature regions.