研究目的
Investigating the fabrication of nBn heterostructures based on AlInSb/InSb for IR photodetectors with reduced dark current.
研究成果
The nBn heterostructures based on AlInSb/InSb demonstrated a significant reduction in dark current density compared to pin structures, due to the efficient blocking of majority carriers by the built-in barrier. The bulk current component was found to prevail over the surface component, indicating relaxed requirements for surface passivation.
研究不足
The study is limited to the characterization of dark current in nBn heterostructures under specific temperature and bias conditions. The influence of other factors such as light exposure or different doping levels was not explored.
1：Experimental Design and Method Selection:
The study involved the fabrication of nBn heterostructures based on AlInSb/InSb for IR photodetectors using molecular-beam epitaxy (MBE). The heterostructures were designed to include a variband AlInSb barrier to block the flow of majority charge carriers.
2：Sample Selection and Data Sources:
The heterostructures were grown on an n-type Te-doped InSb(100) substrate. The layers included a buffer layer, an absorbing layer, a barrier layer, and a contact layer, all doped with Si.
3：List of Experimental Equipment and Materials:
A Riber Compact-21 system was used for MBE growth. Photolithography and wet etching were used to fabricate mesostructures of different diameters. Surface passivation was performed by plasma-chemical SiO2 deposition.
4：Experimental Procedures and Operational Workflow:
Mesostructures with diameters ranging from 200 to 50 μm were fabricated. The dark current was measured at temperatures from 80 to 240 K under bias voltages from -1 to +1 V.
5：Data Analysis Methods:
The dependence of the dark current on mesostructure size was analyzed to determine the dominant current components. Activation energies were calculated to understand the mechanisms of dark current generation.
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