%0 Journal Article
%T Semiconductive properties of anodic niobium oxides
%A S¨¢
%A A.I. de
%A Rangel
%A C.M.
%A Skeldon
%A P.
%A Thompson
%A G.E.
%J Portugaliae Electrochimica Acta
%D 2006
%I Sociedade Portuguesa de Electroqu¨ªmica
%X the semiconductive properties of anodic niobium oxides formed at constant potential and constant current density to different final voltages have been examined by mott-schottky analysis. thin anodic oxides were formed on sputtered niobium specimens at constant potential in the range of 2.5 to 10 vag/agcl in a borate buffer solution. thicker oxides were formed, also on sputtered niobium specimens, at a constant current density of 5 ma cm-2 in 0.1 m ammonium pentaborate solution to final voltages of 10, 50 and 100 v. capacitance measurements were performed in a borate buffer solution of ph 8.8, at a frequency range of 200 to 2000 hz, at a sweep rate of 5 mv s-1 from +2.5 to -1 vag/agcl. the results obtained show n-type semiconductor behaviour with a carrier density in the range of 8 ¡ä 1018 - 6 ¡ä 1019 cm-3 on films formed to 10 v. thicker films showed lower carrier densities in the range of 1 ¡ä 1018 - 2 ¡ä 1018 cm-3 with a calculated charge depletion layer of 33-36 nm.
%K niobium oxides
%K anodic oxides
%K mott-schottky behaviour.
%U http://www.scielo.gpeari.mctes.pt/scielo.php?script=sci_abstract&pid=S0872-19042006000200012&lng=en&nrm=iso&tlng=en