Direct-Conversion X-Ray Detector Using Lateral Amorphous Selenium Structure

作者：Chen Feng^*; Wang Kai; Fang Yuan; Allec Nicholas; Belev George; Kasap Safa; Karim Karim S

来源：IEEE Sensors Journal, 2011, 11(2): 505-509.

DOI：10.1109/JSEN.2010.2061841

• Amorphous selenium
• direct conversion
• metal-semiconductor-metal (MSM) structure
• X-ray imaging

In this paper, we propose to use a lateral metal-semiconductor-metal (MSM) structure with a thick amorphous selenium (a-Se) layer intended for direct-conversion X-ray detection. For the purposes of demonstration, a variety of single-pixel detectors with electrode spacing ranging from 2 to 10 mu m were fabricated and characterized. Compared with the vertical structure, the MSM structure avoids the usage of high voltage, therefore eliminating a safety concern. However, the simulation results indicate that the electric field in such a structure is not uniformly distributed and only confined into a region near the bottom electrodes up to a thickness of similar to 20 mu m. The charge collection is therefore undertaken in the bottom layer and the top layer where a majority of energy deposits instead plays a dominant role in charge generation and diffusion. We believe that the lateral MSM detector with thick a-Se will be feasible for direct-conversion X-ray detection.

• 出版日期2011-2
• 单位Saskatoon; Saskatchewan