Semiconductor nanostructures in an alumina template matrix: micro-versus macro-scale photoelectrochemical behavior

We show herein that the photoelectrochemical behavior of a given semiconductor nanodot (p-CuSCN or n-TiO2) in an alumina template matrix, is remarkably different than that of its macro-sized counterpart. Three separate examples of this distinct difference in behavior are presented. It is shown how the photoresponse (e.g. photocurrent) may be amplified (from a low level typical of the signal emanating from a similar to 10(-11) cm(2) region corresponding to a semiconductor nanodot) by using a large number of electrically inter-connected Au nanowires to support the overlying semiconductor nanodots. The anomalous photoresponse of p-CuSCN nanodots in the template matrix was also numerically simulated by a simple parallel equivalent circuit consisting of a semiconductor and a photocapacitor. Possible practical application scenarios are finally presented for these nanostructures. (C) 2002 Elsevier Science Ltd. All rights reserved.