Resonant Cavity Enhanced Gainassb Infrared Photodetectors

The resonant cavity enhanced (RCE) PIN photodetector has high bandwidth and high sensitivity simultaneously compared with traditional PIN photodetector. In this thesis, we have designed the structure of GaInAsSb/GaSb photodetector in which the light is incident from the substrate. The performance of the device has been simulated. The GalnAsSb PIN photodetector is prepared by MOCVD. The spectral response of the detector is simulated and compared with the measure result.The characteristic of RCE photodetector is analyzed in this thesis. The formula of quantum efficiency is derived and the effect of top reflector to quantum efficiency is discussed. The effect of the resonant cavity is also discussed. It is indicated that the resonant cavity with high Q will enhance the quantum efficiency greatly, especially the higher Q, the more great enhancement. The response of the RCE photodetector has also been analyzed.The feasibility of GaSb/InAs QWS using as DBR in GalnAsSb/GaSb RCE photodetector is demonstrated. The structure of RCE GalnAsSb/GaSb photodetector that the light is incident from the substrate has been designed. The top reflector for this structure is made of 9.5-15.5 periods GaSb/InAs quarter wave stacks (QWS) and the bottom reflector is made of three periods of SiCVSi QWS. The antireflection coating which has more than 99% transmissivity should be deposited on the substrate surface. The simulation shows that the quantum efficiency could be nearly or more than to 90% at design wavelength 2.4um. The cut-off wavelength of the detectors is in the range of 2.48-2.56μ.m. It is shown that the device has two spectral response peaks which could make the device function as double-color detector.The spectral response of PIN GalnAsSb/GaSb photodetector irradiated by 500K black-body radiation source is simulated and compared to the experimental one of the device prepared by MOCVD. It is shown that simulation is closed to the experimental result. The main difference is the spectral response peak of simulation is 2.07μmwhile the experimental result is 2.02u.m. the value of simulation in the long wave region is higher.