Estudo do comportamento fotoeletroquímico de eletrodos semicondutores de n- BaTi03

Abstract

The eletrochemical behavior of semiconductor electrodes of monbcrystaline n-BaTi03 is investigated in the dark and with illumination, using various electrolytes. From these results, interpreted in terns of the physical praperties af the semi canductor, it was determined that the energy af the forbidden band af this material is 3,15eV and that its fundamental aptical transitian is indirect. A determinatian af the flat band patential (V8p) af the semicanductar is also made, using the plat of the square af the phatacurrent versus electrode potencial as well as the Mott-Schattky plat, and which of the two technics gives the results of greater accuracy is alsa discussed. The danars density ND is determined from the l/C 2 x V and the plat af ln(l-n) x (V-V0) l/2 . The plat of values encauntered by the twa techni cs are nat of the sarne arder of magnitude. The mean diffusian length of the minarity carriers, Lp , is determined from plats af ln(l-n) x (V-V0) 1/2 and fram plats of Q x 1/C, which give values differing by ane arder of magnitude. An explanatian af this discrepancy is given.