High-resolution Schottky CdTe diode for hard X-ray and gamma-ray astronomy
High-resolution Schottky CdTe diode for hard X-ray and gamma-ray astronomy
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DOI：
10.1016/s0168-9002(99)00606-3
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发表时间：
1999-10-21
影响因子：
1.4
通讯作者：
Tomita, Y
中科院分区：
文献类型：
--
作者：
Takahashi, T;Paul, B;Tomita, Y
我们报告的碲化镉（CdTe）探测器，在肖特基碲化镉二极管的形式制造的光谱特性的显着改善。我们使用高品质的碲化镉晶片，在碲面蒸镀铟以形成肖特基结，并将侦测器当作二极管来运作。这使我们能够应用比以前的CdTe探测器更高的偏置电压。厚度为0.5 mm的2 mm x 2 mm探测器在5 ℃温度下工作时，在400 V和800 V工作电压下的漏电流分别仅为0.2 nA和0.4 nA。我们发现，在几个kV cm（-1）的高电场下，肖特基CdTe二极管具有非常好的能量分辨率和稳定性，适合于天文应用。宽的低能量的尾巴，经常观察到的CdTe探测器，由于低迁移率和短寿命的空穴，显着减少的应用程序的更高的偏置电压，提高了电荷收集效率。我们实现了非常好的FWHM能量分辨率为1.1%和0.8%，分别在能量122和511千电子伏，没有任何上升时间的歧视或脉冲高度校正电子。对于100 keV以上的硬X射线和γ射线的探测，我们通过堆叠一些薄的CdTe二极管来提高探测效率。使用单独的读出电子的每一层，我们获得了高的检测效率，而不牺牲能量分辨率。在本文中，我们报告的新的碲化镉二极管的性能，并讨论其在未来的硬X射线和伽马射线天文任务的拟议应用。(C)1999 Elsevier Science B. V.保留所有权利。
We report a significant improvement of the spectral properties of cadmium telluride (CdTe) detectors, fabricated in the form of a Schottky CdTe diode. With the use of high quality CdTe wafer, we formed a Schottky junction by evaporating indium on the Te-face and operated the detector as a diode. This allows us to apply much higher bias voltage than was possible with the previous CdTe detectors. A 2 mm x 2 mm detector of thickness 0.5 mm, when operated at a temperature of 5 degrees C, shows leakage current of only 0.2 and 0.4 nA for an operating voltage of 400 and 800 V, respectively. We found that, at a high-electric field of several kV cm(-1), the Schottky CdTe diode has very good energy resolution and stability, suitable for astronomical applications. The broad low-energy tail, often observed in CdTe detectors due to the low mobility and short lifetime of holes, was significantly reduced by the application of a higher bias voltage which improves the charge collection efficiency. We achieved very good FWHM energy resolution of 1.1% and 0.8% at energies 122 and 511 keV, respectively, without any rise time discrimination or pulse height correction electronics. For the detection of hard X-rays and gamma-rays above 100 keV, we have improved the detection efficiency by stacking a number of thin CdTe diodes. Using individual readout electronics for each layer, we obtained high detection efficiency without sacrificing the energy resolution. In this paper, we report the performance of the new CdTe diode and discuss its proposed applications in future hard X-ray and gamma-ray astronomy missions. (C) 1999 Elsevier Science B.V. All rights reserved.