Obtenção de filmes espessos de seleneto de cobre sobre carbono vítreo, ouro, titânio e cobre

Abstract

Recebido em 11/10/05; aceito em 31/5/06; publicado na web em 28/11/06 OBTAINING COPPER SELENIDE THICK FILMS ON VITREOUS CARBON, GOLD, TITANIUM AND COPPER. Copper selenide (berzelianite) films were prepared on the title substrates using the chemical bath deposition technique (CBD). Film composition was determined by energy dispersion of x-rays. The kinetics of film growth is parabolic and film adherence limits the film thickness. On titanium, copper selenide forms islands that do not completely cover the surface, unless the substrate is prepared with a tin oxide layer; film composition also depends on the titanium oxide layer. On vitreous carbon, CBD and mechanical immobilization techniques lead to films with similar resistances for the electron transfer across the film/substrate interface. On gold, composition studies revealed that film composition is always the same if the pH is in the range from 8 to 12, in contrast to films prepared by an ion-ion combination route. On copper, a new procedure for obtaining copper selenide films as thick as 5 μm has been developed.

Crystallization at room temperature from amorphous to trigonal selenium as a byproduct of the synthesis of water dispersible zinc selenide

“…For these syntheses, the selenium sources often applied can be either commercial reactants, such as sodium selenite (NaSeO 3 ) [11], or in situ yielded selenium species, like sodium selenosulfide (NaSeSO 3 ), formed from the reduction of elemental selenium by sodium sulfite [12]. Another selenium source usually used is sodium hydrogen selenide (NaHSe) obtained from reduction of elemental selenium by sodium borohydride (NaBH 4 ) [13,14].…”