Properties of nanostructures realized by bottom-up techniques are often different from their bulk counterparts.(1) Here we present a study of a nano-Schottky contact formed at the interface between a gold catalytic particle and an epitaxially grown Ga(x)In(1-x)As/InAs nanowire. Selective electrical connections formed to the catalytic particle on one side and to the In As segment on the other side allowed electrical and optical characterization of the formed junction. We demonstrate that the heterostructure region adjacent to the catalytic particle may act as an ultra-small volume unipolar photodetector with potentially ultra-fast response.