研究目的
Investigating the tunnel-induced photocarrier escape processes in a laterally coupled InAs sub-monolayer quantum dot-based photodetector as a function of fractional coverage from 0.4 ML to 0.8 ML.
研究成果
The study concludes that by varying the SML coverage, it is possible to control the relative time scales of interband recombination and carrier tunneling, which essentially determine the overall detector performance. Higher coverage fractions lead to faster photoresponse and greater responsivity, with the potential for near room temperature photodetection.
研究不足
The study is limited to the investigation of InAs/GaAs sub-monolayer quantum dot-based photodetectors with fractional coverage from 0.4 ML to 0.8 ML. The performance and applicability of the findings to other materials or coverage ranges are not explored.
1:Experimental Design and Method Selection:
The study involves both simulation and experimental approaches to quantitatively describe the temperature dependent interband photoresponse.
2:Sample Selection and Data Sources:
The samples are based on InAs/GaAs SML QD heterostructures grown on a semi-insulating GaAs substrate by molecular beam epitaxy (MBE).
3:List of Experimental Equipment and Materials:
Equipment includes Keithley 4200 SCS and Tektronix TBS2102 digital storage oscilloscope (DSO), a 450 W xenon lamp in conjunction with a Gemini-180 monochromator, and atomic force microscopy (AFM) for imaging.
4:Experimental Procedures and Operational Workflow:
The current-voltage characteristics of QDIP devices and the temporal variation of the photocurrent at constant bias were performed. Spectral photoresponse of the detector were measured.
5:Data Analysis Methods:
The temperature dependence of photocurrent was modeled by a simple rate-equation of the carrier population in a given QD level for a photocarrier generation rate.
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