Browse Prior Art Database

New Photoconductor

IP.com Disclosure Number: IPCOM000089617D
Original Publication Date: 1977-Nov-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Esaki, L: AUTHOR [+2]

Abstract

A photoconductor with high sensitivity and reduced dark current can be constructed in a GaAs-Ga(x)Al(1 - x) As superlattice, where the well width and barrier width are in the vicinity of 90 Angstroms and the barrier height is in the vicinity of 100 meV.

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New Photoconductor

A photoconductor with high sensitivity and reduced dark current can be constructed in a GaAs-Ga(x)Al(1 - x) As superlattice, where the well width and barrier width are in the vicinity of 90 Angstroms and the barrier height is in the vicinity of 100 meV.

As may be seen from the figures, the barrier height E(B), the barrier width b and the well width a (Fig. 1) result in conditions that electrons in the second sub- band (E(1) ~E(1) + Delta E(1)) are only loosely confined by the well. The concentration of electrons is chosen so that electrons populate only the lowest sub-bands. Current flows perpendicularly to the superlattice plane, as shown in Fig. 2.

Because of the strong electron confinement, the mobility of electrons in the lowest sub-band becomes virtually zero, whereas the mobility of loosely confined electrons in the higher sub-band takes a finite value and thereby results in increased sensitivity.

The spectral response is schematically shown in Fig. 3 where the peaks correspond to a series of higher sub-bands. By controlling superlattice configurations, the peak locations and widths can be controlled, and freedom in spectral sensitivity is achieved.

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