Thomas S Mcgill

US Patent:

53714091, Dec 6, 1994

Filed:

Nov 16, 1993

Appl. No.:

8/153783

Inventors:

James O. McCaldin - San Diego CA
Thomas C. McGill - Pasadena CA
Mark C. Phillips - Pasadena CA

Assignee:

California Institute of Technology - Pasadena CA

International Classification:

H01L 2300
H01L 2978

US Classification:

257741

Abstract:

Type-II semiconductor heterojunction light emitting devices formed on a substrate are described wherein a graded injection layer is used to accelerate electrons over the electron barrier formed by the junction. Further, wide band gap semiconductor LEDs and lasers are proposed formed of II-VI materials which emit light in the blue and green wavelengths. Particularly, a system composed of n-CdSe:Al/Mg. sub. x Cd. sub. 1-x Se/Mg. sub. y Zn. sub. 1-y Te/p-ZnTe are described where the value of y determines the wavelength of the emitted light in the green or blue region and x varies across the graded injection layer for raising the energy levels of excited electrons.

US Patent:

56464193, Jul 8, 1997

Filed:

Apr 7, 1995

Appl. No.:

8/418274

Inventors:

James O. McCaldin - San Diego CA
Michael W. C. Wang - Pasadena CA
Thomas C. McGill - Pasadena CA

Assignee:

California Institute of Technology - Pasadena CA

International Classification:

H01L 2906
H01L 3300

US Classification:

257 13

Abstract:

n-type wide bandgap semiconductors grown on a p-type layer to form hole injection pn heterojunctions and methods of fabricating the same. In a preferred embodiment, a p-type gallium nitride substrate is used. A first layer, such as a magnesium zinc sulfide layer Mg. sub. x Zn. sub. 1-x S is then deposited. Thereafter, a second layer such as an n-type zinc sulfide layer is deposited. The magnesium zinc sulfide layer forms an electron blocker layer, and preferably is adequately thick to prevent significant tunneling of electrons there through. Thus, the primary charge flow across the heterojunction is by way of holes injected into the n-type zinc sulfide region from the p-type gallium nitride region, resulting in electron-hole recombination in the zinc sulfide region to provide light emission in the wide bandgap zinc sulfide material. Alternate embodiments are disclosed.