Accession Number:

AD0614676

Title:

HETEROJUNCTION DEVICES.

Descriptive Note:

Final rept., 1 May 63-30 Nov 64,

Corporate Author:

SYRACUSE UNIV N Y COLL OF ENGINEERING

Report Date:

1965-03-01

Pagination or Media Count:

129.0

Abstract:

The opto-electric characteristics of abrupt Ge-GaAs heterojunctions have been investigated to determine if such devices are efficient photon detectors. Because of a notch in the band edge at the interface the quantum efficiency is low. Further, such a device as the collector in an optical transistor is concluded to be impractical. A method of determining the minority carrier lifetime in the Ge adjacent to the GaAs, from the photocurrent spectrum, is developed. Near the band gap of Ge, the photocurrent spectrum exhibits changes in slope attributable to the onset of phonon assisted absorption. An efficient photodetector is described which utilizes a Ge-Si n-n heterojunction. A qualitative theory for this is developed. Photo-excited holes are trapped in the notch in the valence band which in turn modulates the diode current. Attempts to fabricate a wide band gap transistor have been unsuccessful. It was determined that a poor injection efficiency resulting from a predominance of recombination current in the GaAs is at fault. An apparatus for probing semiconductor devices is described. The thermoelectric and photovoltaic methods are used. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE