Optimal width of barrier region in X/γ-ray Schottky diode detectors based on CdTe and CdZnTe

被引：26

作者：

Kosyachenko, L. A. ^{[1
]}

Aoki, T. ^{[2
]}

Lambropoulos, C. P. ^{[3
]}

Gnatyuk, V. A. ^{[4
]}

Melnychuk, S. V. ^{[1
]}

Sklyarchuk, V. M. ^{[1
]}

Grushko, E. V. ^{[1
,2
]}

Maslyanchuk, O. L. ^{[1
]}

Sklyarchuk, O. V. ^{[1
]}

机构：

[1] Chernivtsi Natl Univ, UA-58012 Chernovtsy, Ukraine

[2] Shizuoka Univ, Elect Res Inst, Joho Ku, Hamamatsu, Shizuoka 4328011, Japan

[3] Technol Educ Inst Chalkida, GR-34400 Psahna, Evia, Greece

[4] Natl Acad Sci Ukraine, Inst Semicond Phys, UA-03028 Kiev, Ukraine

来源：

JOURNAL OF APPLIED PHYSICS | 2013年 / 113卷 / 05期

关键词：

HARD X-RAY; MECHANISM; CRYSTALS;

D O I：

10.1063/1.4790358

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

The spectral distribution of quantum detection efficiency of X- and gamma-ray Schottky diodes based on semi-insulating CdTe or Cd0.9Zn0.1Te crystals is substantiated and obtained in analytical form. It is shown that the width of the space charge region (SCR) of 6-40 mu m at zero bias in CdTe (Cd0.9Zn0.1Te) Schottky diode is optimal for detecting radiation in the photon energy range above 5-10 keV. Based on the Poisson equation, the relationship between the SCR width and the composition of impurities and the degree of their compensation are investigated. It is shown that the presence of deep levels in the bandgap leads to a considerable increase in space charge density and electric field strength near the crystal surface. However, this effect contributes a small error in the determination of the SCR width using the standard formula for the Schottky diode. It is also shown that the concentration of uncompensated impurities in CdTe and Cd0.9Zn0.1Te crystals within the 4 x 10(11) - 10(13) cm(-3) range is optimal for the detection efficiency of X-and gamma-rays in the photon high-energy range. The record-high values of energy resolution have been obtained in the spectra of Am-241, Co-57, Ba-133 and Cs-137 isotopes measured using CdTe crystals with Schottky diodes because the concentration of uncompensated donors in the CdTe crystals (1-2) x 10(12) cm(-3) falls on an interval of maximum detection efficiency. In the spectrum of Co-57 isotope, the limiting energy resolution has been achieved. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4790358]

引用

页数：9

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