In this work a novel device structure of a photoconductive sensor manufactured in In0.52Al0.48As/In0.53Ga0.47As heterostructures with a 100 nm wide T shape gate patterned on the top of a two dimensional electron gas (2DEG) was proposed. The nanosize gate defines the ultra short conducting channel underneath it, leading to the ballistic transport of the photoconductive electrons. The photo-electronic response in the infrared wavelength of 1.16 mu m was measured under various gate voltages. The working mechanism and the prospect of such kind of sensors were discussed. (C) 2007 Elsevier Ltd. All rights reserved.