Articles you may be interested inEvanescent-coupled antireflection coatings for hyper-numerical aperture immersion lithography J. Vac. Sci. Technol. B 32, 06FE03 (2014); 10.1116/1.4900726 Talbot effect immersion lithography by self-imaging of very fine grating patterns

A four 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 by utilizing a cooled substrate or a high thermal conductivity substrate under the GaN films.

No abstract

Formation of cesium peroxide and cesium superoxide on InP photocathode activated by cesium and oxygenNegative electron affinity group III-nitride photocathode demonstrated as a high performance electron source Experimental results on a new CsBr/ GaN heterojunction photocathode structure are presented. The results indicate a fourfold improvement in photoyield relative to CsBr/ Cr photocathodes. A model is presented based on intraband states in CsBr and electron injection from the GaN ͑with 1% addition of indium͒ substrate to explain the observed photoyield enhancement. The photocathode lifetime at high current density ͑Ͼ40 A / cm 2 ͒ is limited by laser heating of the small illuminated area. Calculations are presented for sapphire and diamond substrates, indicating a factor of 20 reduction in temperature for the latter. The results are encouraging for the realization of a high photoyield photocathode operating at high current density with long lifetime.

No abstract