| Popis: |
Epitaxial growth of a high-quality InSb layer on a mismatched substrate which provides a path to monolithically integrate InSb-based photonic devices and Si/GaAs-based electronic devices on a single wafer. This work is an attempt to investigate the effects of In0.9Al0.1Sb electron barrier layers on the electrical and optical properties of the InSb photodetectors on a mismatched substrate. The structure of InSb photodetector is p-i-n type where i-layer is the unintentionally n-type doped. A 25 nm In0.9Al0.1Sb layer locates in the i-layer. At 77 K, InAlSb barrier can effectively decrease dark current due to it completely suppresses the generation and recombination current and tunneling current and partially suppresses the diffusion current. The different dark current mechanisms (diffusion, generation and recombination, tunneling) are discussed associated with the bandgap diagrams. For the simulation of photoresponse, the incident light is set to be 5.3 μm. At 77 K, the existence of InAlSb layer doesn’t influence the absorption of incident light due to its limited thickness, however, the InAlSb layer separates the i-layer and impedes the transportation of electrons. Therefore, the InAlSb layer decrease the photoresponse of InSb detector and its effects is more remarkable when the diffusion length of hole is around 5 μm or its location is near the surface of the detector. According to the simulation, optimizing the location of the In0.9Al0.1Sb is important to increase the performance of InSb photodetectors on a mismatched substrate. |
