ROCKWELL INTERNATIONAL THOUSAND OAKS CA SCIENCE CENTER
The design and progress towards development of a field-assisted double heterojunction photocathode with high quantum efficiency at 1.06 micrometers is reported. This project covers three main areas 1 The growth by liquid phase epitaxy and characterization of GaAsSb and GaAlAsSb alloys of suitable composition for fabricating a heterojunction photocathode. 2 Experimental and theoretical studies on the electron and hole transport and optical properties of heterojunctions between various III-V alloys grown by liquid phase epitaxy. 3 The design, fabrication and testing of a double heterojunction p-n-p photocathode structure with a p-n junction collector. Experimental studies on the electrical transport and optical properties of the heterojunctions required for the photocathode show that the anticipated problems with potential barriers in the conduction band do not exist. These results have significant implications for many other heterojunction devices. Internal photoemission in the complete photocathode test structure has been observed establishing the feasibility of the double heterojunction approach.