Carrier transport mechanism associated with the thickness of the absorbing layer in GaAs-based blocked‐impurity‐band (BIB) far‐infrared detectors

Carrier transport mechanism associated with the thickness of the absorbing layer in GaAs-based blocked-impurity-band (BIB) far-infrared detector has been investigated in detail. It is found that responsivity linearly increases with the increased thickness of absorbing layer first, and after achieving a peak value, and then starts dropping slowly. In order to explore the carrier transport mechanism behind the phenomena, the physical meaning of responsivity has been illuminated first, and then the vertical profiles of the optical generation rate, the electric field intensity, and the carrier mobility have been obtained, respectively. It is demonstrated that the carrier transport mechanism associated with the thickness of the absorbing layer can be attributed to the competing effects of the optical generation rate, the electric field intensity, and the carrier mobility.