Development of Large-Area CdTe/n(+) -Si Epitaxial Layer-Based Heterojunction Diode-Type Gamma-Ray Detector Arrays

作者：Niraula M^*; Yasuda K; Kojima M; Kitagawa S; Tsubota S; Yamaguchi T; Ozawa J; Agata Y

来源：IEEE Transactions on Nuclear Science, 2018, 65(4): 1066-1069.

DOI：10.1109/TNS.2018.2812154

• Arrays
• CdTe
• epitaxial growth
• gamma detectors
• large-area crystal
• response uniformity

Growth of large area single crystal CdTe layers was studied on 25 x 25 mm(2) (211) Si substrates using metalorganic vapor phase epitaxy. High crystalline quality thick crystals with very good material uniformity were obtained. A 2-D monolithic detector array comprising (20 x 20) pixels was developed and evaluated. Each pixel is 1.12 x 1.12 mm(2) size in a 1.17-mm pitch and consists of a p-CdTe/n-CdTe/n(+)-Si heterojunction diode structure, which is isolated from the surrounding pixels by making deep vertical cuts. The detector array exhibited highly uniform and low dark current, typically less than 0.5-mu A/cm(2) per pixel at an applied reverse bias of 50 V. The spectroscopic performance was separately confirmed by dicing out a small portion from the array which clearly resolved energy peaks from Am-241 gamma isotopes at room temperature. On the other hand, a significant improvement in the detection property was observed by cooling it to -30 degrees C.

• 出版日期2018-4