Accession Number:

AD0648089

Title:

SEMICONDUCTOR OPTICAL SHUTTER.

Descriptive Note:

Final rept. 1 Nov 65-30 Sep 66

Corporate Author:

GENERAL ELECTRIC CO OKLAHOMA CITY OKLA OKLAHOMA CITY COMPUTER OPERATION

Personal Author(s):

Report Date:

1966-12-01

Pagination or Media Count:

56.0

Abstract:

The objective of the Semiconductor Optical Shutter program was to investigate the feasibility of using a normally transparent semiconductor as a viewing panel which can, by proper stimulation, be rendered opaque rapidly, and which can be returned promptly to its normal, transparent state. The proposed approach was to produce a very high concentration of free charge carriers so that the normally transparent, insulating semiconductor becomes almost metallic and exhibits metal-like optical reflection and absorption characteristics. Carrier injection at a p-n junction, or carrier excitation by irradiation with electrons or with band-gap radiation h nu or Eg would be potential means for producing the needed high density of free carriers, but only the latter method was explored. Materials were evaluated by determining the transmission of visible radiation before and during exposure to high intensity bursts of ultraviolet light from a xenon flashtube. Rutile TiO2 showed no effect at incident ultraviolet photon densities of approximately 10 to the 18th power photonssq cm in approximately 400 microsec bursts. A sample of SrTiO3 showed about a 12 decrease of transmission under similar irradiation, and a CdS sample showed a decrease of 30 with slightly higher excitation. These results are interpreted in terms of the physical processes occurring. It appears that further work with these and related materials with special attention to surface preparation would result in materials offering good prospects for a successful semiconductor optical shutter.

Subject Categories:

  • Optics
  • Solid State Physics
  • Protective Equipment

Distribution Statement:

APPROVED FOR PUBLIC RELEASE