sci 32 1997 pp 3349 3353 other embodiments may employ sio formed as described in u201c production of sio 2 films over large substrate area by ion assisted deposition of sio with a cold cathode source u201d by i c stevenson soc of vac coaters proc 36 th annual tech conf 1993 pp 88 93 or u201c improvement of the ito p interface in u03b1 si h solar cells using a thin sio intermediate layer u201d by c nunes de carvalho et al proc mrs spring symposium vol 420 1996 pp 861 865 together with a co deposited metal other metals e g cr au cu etc may be used to form cermet or cermet like materials as described by zaidi et al in a step 110 the emitter tips 30 b are formed fig6 f by deposition of a layer 111 in one embodiment the layer 111 and the emitter tips 30 b are formed by evaporation of one of the materials listed in table i that are amenable to deposition by vacuum evaporation tin may be formed in situ by evaporation of a thin ti film e g two hundred angstroms or more followed by rapid thermal annealing in a nitrogen bearing atmosphere e g ammonia in other embodiments other materials may be sputtered or may be deposited by chemical vapor deposition in one embodiment silicon oxycarbide is employed as the emitter tips 30 b in the step 110 a process for forming thin microcrystalline films of silicon oxycarbide is described in u201c transport.