REPORT DOCUMENTATION PAGE					Form Approved OMB No. 0704-0188
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1. AGENCY USE ONLY (Leave Blank)		2. REPORT DATE 31 Dec 1997	3. REPORT TYPE AND DATES COVERED Final Progress 1Jan 95 – 31 May 99
4. TITLE AND SUBTITLE Non-Cesiated Solid State Electron Emitters (Cold Cathodes) & Their Applications in Vacuum Microelectronics					5. FUNDING NUMBERS DAAH04-95-1-0157
6. AUTHORS Prof. Umesh K. Mishra Robert D. Underwood
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Department of Electrical & Computer Engineering University of California, Santa Barbara Santa Barbara, CA 93106					8. PERFORMING ORGANIZATION REPORT NUMBER
9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211					10. SPONSORING / MONITORING AGENCY REPORT NUMBER 33799-PH
11. SUPPLEMENTARY NOTES The views, opinions and/or findings contained in this report are those of the author(s) and should not be construed as an official Department of the Army position, policy or decision, unless so designated by other documentation.
12a. DISTRIBUTION / AVAILABILITY STATEMENT Approved for public release; distribution unlimited.					12b. DISTRIBUTION CODE
13. ABSTRACT (Maximum 200 words) Stable, non-cesiated cold cathodes hold much promise for high power and high efficiency vacuum electronics. Cesium is typically used to lower the surface barrier to electron emission, but cesium presents problems with reliability and lifetime. GaN-based cold cathodes have the advantage of having a low surface barrier and a stable surface, both of which are beneficial for cold cathode electron emission. Better performance, in terms of lower operating voltage and higher current density, can be achieved by further decreasing the size of the surface tunnel barrier of field emitter-based cold cathodes. The large piezoelectric field produced in pseudomorphically grown InGaN layers on GaN field emitter pyramids allows the reduction of the surface energy barrier. Experiments have shown that the amount of barrier lowering increases with increasing InGaN thickness up to some critical thickness where the effects of strain relaxation and scattering reduce the effect of the piezoelectric barrier lowering. Results of an experiment have shown an effective electron affinity of 1 eV, which is reduced 70% from the electron affinity of GaN, 3.5 eV. The effective of the electron affinity reduction is to reduce the turn-on voltage of the field emitter arrays, from 300 V to 150 V.
14. SUBJECT TERMS GaN, field emitter array, vacuum microelectronics, integrated anode, piezoelectric effect						15. NUMBER OF PAGES
pseudomorphic growth, InGaN						16. PRICE CODE
17. SECURITY CLASSIFICATION OF REPORT UNCLASSIFIED	18. SECURITY CLASSIFICATION OF THIS PAGE UNCLASSIFIED			19. SECURITY CLASSIFICATION OF ABSTRACT UNCLASSIFIED		20. LIMITATION OF ABSTRACT UL
NSN 7540-01-280-5500						Standard Form 298 (Rev. 2-89) Prescribed by ANSI Std. Z39-1 298-102