Abstract This work investigates the potential of CdTe semiconducting layers used for radiation detection directly deposited on the Medipix readout-chip by MBE. Due to the high Z-number of CdTe and the low electron-hole pair creation energy a thin layer suffices for satisfying photon absorption. The deposition takes place in a modified MBE system enabling growth rates up to 10 µm/h while the UHV conditions allow the required high purity for detector applications. CdTe sensor layers deposited on silicon substrates show resistivities up to 5.8 × 10 8 Ω cm and a preferred (1 1 1) orientation. However, the resistivity increases with higher growth temperature and the orientation gets more random. Additionally, the deposition of a back contact layer sequence in one process simplifies the complex production of an efficient contact on CdTe with aligned work functions. UPS measurements verify a decrease of the work function of 0.62 eV induced by Te doping of the CdTe.

中文翻译：

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通过 MBE 在 Medipix 读出芯片上直接生长的用于 X 射线和伽马射线检测的 CdTe 层结构

摘要 这项工作研究了通过 MBE 直接沉积在 Medipix 读出芯片上的用于辐射检测的 CdTe 半导体层的潜力。由于 CdTe 的高 Z 数和低电子-空穴对产生能量，薄层足以满足光子吸收。沉积在改进的 MBE 系统中进行，可实现高达 10 µm/h 的生长速率，而 UHV 条件允许检测器应用所需的高纯度。沉积在硅衬底上的 CdTe 传感器层显示出高达 5.8 × 10 8 Ω cm 的电阻率和优选的 (1 1 1) 取向。然而，电阻率随着生长温度的升高而增加，取向变得更加随机。此外，在一个过程中沉积背接触层序列简化了在 CdTe 上具有对齐功函数的有效接触的复杂生产。UPS 测量验证了 CdTe 的 Te 掺杂引起的 0.62 eV 功函数的降低。