Microdischarge Studied for Detectors

Scientists at the University of Illinois in Urbana and at Ewing Technology Associates in Bellevue, Wash., are investigating the photosensitivity of silicon microdischarge devices. Experiments at the university, reported in the Dec. 9 issue of Applied Physics Letters, characterized the detection of UV, visible and near-IR radiation by the devices, finding responses as high as 950 ±250 A/W at 625 nm for a 50 x 50-µm device.

In microdischarge devices, the semiconductor serves as a photocathode and the plasma acts as an electron multiplier via an avalanche process. Gary Eden of the University of Illinois said that it should be possible to develop a family of microdischarge photodetectors that operate over a wide wavelength by using a semiconductor with a bandgap different from that of the photocathode. Arrays of the devices may be used in spectroscopy and biochemic applications.