Study on the Development of InSb Radiation Detectors with High Efficicency and High Energy Resolution at Low Operating Temperature

对InSb进行了晶体生长。在上一财年，我们获得了一个单晶，晶体速度为0.47 mm/h。所用原料为In和Sb，其纯度均大于99.9999%。晶体生长后，我们把晶体切成晶片。对于晶体顶部、中间和末端的三个晶圆，以及商业InSb晶圆，进行了化学计量学检查。此外，还测量了这些晶圆的电阻率、载流子浓度和霍尔迁移率等电性能作为工作温度的函数。从这些测量中，发现InSb的电学性质比化学计量学对杂质更敏感。为了测量辐射，制作了直径为1mm的未掺杂InSb探测器。利用该InSb探测器探测到Ba-133发射的伽马射线，观测到81 keV的能量峰和55 keV的逸出峰。通过模拟程序EGS4计算了InSb探测器损耗层厚度变化时55 ~ 81 keV峰的事件比。通过模拟，确定损耗层的有效厚度为3微米。

Crystal growth of InSb was carried out. In the previous fiscal year, we have got a single crystal with the crystal velocity of 0.47 mm/h. The employed raw materials were In and Sb with their purities greater than 99.9999 %. After the crystal growth, we have cut the crystal into wafers. For the three wafers at the top, middle and end of the crystal were examined for stoichiometry, as well as commercial InSb wafers. Also, electric properties such as resistivity, carrier concentration and Hall mobility were measured for these wafers as a function of operating temperature. From these measurements, the electric properties of InSb were found more sensitive to the impurities than stoichiometry.For the measurements of radiation, undoped InSb detectors with 1 mm diameter were fabricated. With this InSb detector, gamma ray emitted by Ba-133 were detected and the energy peak of 81 keV and its escape peak, 55 keV, were observed. The event ratio of the peaks of 55 keV to 81 keV were calculated by the simulation code EGS4 with changing the thickness of the depletion layer of InSb detector. From this simulation, the effective thickness of the depletion layer was determined as 3 micro-m.