Abstract's Details

A High Current Density GaN/CsBr Heterojunction Photocathode with Improved Photoyield
Abstract ID	MAT-01
Presenter	Zhi Liu
Presentation Type	Poster
Full Author List	Z. Liu (1), J. Maldonado (2), Y. Sun (1), P. Pianetta (1), R. F. W. Pease (2)
Affiliations	(1) Stanford Synchrotron Radiation Laboratory (2) Dept. of Electrical Engineering, Stanford University
Category	Materials Science
Abstract	A 4-fold improvement in photoyield has been observed in GaN films coated with CsBr films (CsBr/GaN) relative to CsBr/Cr photocathodes reported in previous studies. A model is presented involving photoemission from intraband states in the CsBr film and direct electron injection through the CsBr film from the GaN substrate. The lifetime of the films at high current density >90A/cm2 is limited by the temperature rise in the GaN films caused by the high photon absorption at 257nm. The lifetime can be improved utilizing a cooled substrate or a high thermal conductivity substrate under the GaN films.
Footnotes
Funding Acknowledgement	This work was supported by a DARPA Grant F33615-00-1-1728 monitored by the Air Force office. Portions of this research were carried out at the Stanford Synchrotron Radiation Laboratory, a national user facility operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences.