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Dynamic Wavelength-Tunable Photodetector Using Subwavelength Graphene Field-Effect Transistors
François Léonard1, Catalin D Spataru1, Michael Goldflam2
1Sandia National Laboratories, Livermore, CA, 94551, United States.
Scientific Reports
|April 5, 2017
Summary
Dynamic wavelength tunability in graphene photodetectors is achievable by adjusting gate voltage. This study reveals novel phenomena enhancing non-vertical optical transitions for tunable light detection.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Dynamic wavelength tunability is a key goal for advanced photodetector technology.
- Graphene's unique properties offer potential for tunable photodetectors, but experimental realization has been challenging.
Purpose of the Study:
- To investigate the theoretical possibility of achieving dynamic wavelength tunability in graphene field-effect transistor (GFET) photodetectors.
- To elucidate the underlying physical mechanisms governing photocurrent behavior and optical transitions in GFETs.
Main Methods:
- Utilizing detailed quantum transport modeling of photocurrent in GFETs.
- Incorporating realistic electromagnetic field effects and spatially varying potentials.
Main Results:
- Demonstrated wavelength tunability by dynamically altering the gate voltage.
- Identified strong electromagnetic field focusing at contact edges, enhancing non-vertical optical transitions.
- Observed gate-dependent photocurrent modulation due to contact blocking caused by vanishing density of states near the Dirac point.
Conclusions:
- Dynamic wavelength tunability in graphene photodetectors is theoretically feasible through gate voltage modulation.
- Non-vertical optical transitions play a dominant role, influenced by electromagnetic field focusing and band-bending.
- The findings have implications for a wide range of 1D and 2D material-based devices.