Zero-bias photodetection in 2d materials via geometric design of contacts
arXiv:2303.16782 · doi:10.1021/acs.nanolett.3c01259
Abstract
Structural or crystal asymmetry are necessary conditions for emergence of zero-bias photocurrent in light detectors. Structural asymmetry has been typically achieved via doping being a technologically complex process. Here, we propose an alternative approach to achieve zero-bias photocurrent in 2d material flakes exploiting the geometrical non-equivalence of source and drain contacts. As a prototypical example, we equip a square-shaped flake of PdSe with mutually orthogonal metal leads. Upon uniform illumination with linearly-polarized light, the device demonstrates non-zero photocurrent which flips its sign upon 90 polarization rotation. The origin of zero-bias photocurrent lies in polarization-dependent lightning-rod effect. It enhances the electromagnetic field at one contact from the orthogonal pair, and selectively activates the internal photoeffect at the respective metal-PdSe Schottky junction. The proposed technology of contact engineering can be extended to arbitrary 2d materials and detection of both polarized and natural light.
References in corpus (8)
- Graphene photodetectors for high-speed optical communications
- Palladium Diselenide Long-Wavelength Infrared Photodetector with High Sensitivity and Stability
- Terahertz and Infrared Spectroscopy of Gated Large-Area Graphene
- Fast and Sensitive Terahertz Detection Using an Antenna-Integrated Graphene pn Junction
- Hot-carrier photocurrent effects at graphene-metal interfaces
- Terahertz photoconductivity in bilayer graphene transistors: evidence for tunneling at gate-induced junctions
- Polarization-resolving graphene-based mid-infrared detector
- THz ratchet effect in HgTe interdigitated structures