The authors have demonstrated a novel CdTe x-ray sensing device that consists of a CdTe pn diode and a graphite nanoneedle field emitter. The CdTe diode was fabricated using an excimer laser doping method. The signal current was successfully read out by an electron beam from the field emitter and was found to be proportional to the x-ray intensity. The operation principle of the device is expounded in this article. (c) 2007 American Vacuum Society.