Nanophotonic MOS Solar-Blind Avalanche UV Detectors

Dartmouth College, Hanover NH

Investigators

Abstract

The objective of this research is to invent a new device structure of solar-blind ultraviolet detectors for a broad range of applications, from homeland security to environmental monitoring. Instead of relying on semiconductors with wide band gaps >4 eV, the approach is based on a novel nanophotonic metal-oxide-semiconductor structure coupled with avalanche gain in Si. Compared to wide band gap semiconductor devices, this device structure offers much easier materials deposition, device fabrication, and integration with Si read-out circuits. The intellectual merits of this research are: (1) The proposed device structure sets a new paradigm for solid-state photodetectors by using metal instead of semiconductor as an active photon absorption medium; (2) The investigations on hot electron ballistic transport in metals will explore a new territory applicable to other devices such as high-efficiency solar cells; and (3) Engineering the electronic structures of metal alloys for active metallic optoelectronic devices extends the realm of band engineering beyond semiconductors. The project makes a broader impact by providing high performance, inexpensive solar-blind ultraviolet detectors for a broad range of applications, including early missile warning, ozone-hole monitoring, chemical/biological sensing, and secure short-range communications. An example is large-scale mapping of ultraviolet radiation associated with ozone depletion, where data can be collected by groups of K-12 students in their local region. Such activities get them involved into scientific research and raise their awareness of environmental sustainability. The nanophotonic solar-blind ultraviolet detectors can also equip Arctic researchers to monitor ozone holes in the Arctic region.