Characterization of Cd0.9Zn0.1Te schottky diodes for high resolution nuclear radiation detectors

High barrier cadmium zinc telluride (CZT) Schottky diodes with very low reverse leakage current have been fabricated and characterized for high resolution gamma ray detectors. The diodes were made using Cd0.9Zn0.1Te detector grade crystals grown from zone refined Cd, Zn, and Te (7N) precursor materials using low temperature tellurium solvent method. Various crystallographic defects due to Te-inclusions/precipitates were identified and characterized using electron beam induced current (EBIC) measurement technique for the first time. The EBIC images were correlated very well with transmission infrared (TIR) images of CZT crystals and the EBIC contrast was attributed to the nonuniformities in spatial distribution of Te inclusions. Further characterization by the thermally stimulated current (TSC) spectroscopy revealed shallow and deep level centers with activation energies 0.25– 0.4 eV and 0.65 – 0.8 eV respectively, which was attributed to intrinsic defects associated with Te inclusions. Pulse height spectra (PHS) measurements were carried out using 137Cs (662 keV) radiation source and energy resolution of ∼1.51% FWHM was obtained from the as-grown boule.

[1]  Timothy C. Hayes,et al.  Thermally stimulated current and high temperature resistivity measurements of 4H semi-insulating silicon carbide , 2011 .

[2]  Sandip Das,et al.  Characterization of 4H Semi-Insulating Silicon Carbide Single Crystals Using Electron Beam Induced Current , 2011 .

[3]  K. Mandal,et al.  Ab Initio Studies of Hydrogen Defects in CdTe , 2009 .

[4]  Michael Groza,et al.  Component Overpressure Growth and Characterization of High-Resistivity CdTe Crystals for Radiation Detectors , 2007 .

[5]  Kelvin G. Lynn,et al.  Study of defect levels in CdTe using thermoelectric effect spectroscopy , 2006 .

[6]  D. Look,et al.  Thermally stimulated current spectroscopy of high-purity semi-insulating 4H-SiC substrates , 2005 .

[7]  Michael Groza,et al.  Crystal growth, characterization, and testing of Cd0.9Zn0.1Te single crystals for radiation detectors , 2004, SPIE Optics + Photonics.

[8]  S. Maximenko,et al.  Electron-beam-induced current observed for dislocations in diffused 4H-SiC P-N diodes , 2004 .

[9]  Kelvin G. Lynn,et al.  Electrical compensation in CdTe and Cd 0.9 Zn 0.1 Te by intrinsic defects , 2000 .

[10]  Kelvin G. Lynn,et al.  Electrical compensation in CdTe and CdZnTe by intrinsic defects , 2000, SPIE Optics + Photonics.

[11]  U. Desnica,et al.  PRECISE DETERMINATION OF DEEP TRAP SIGNATURES AND THEIR RELATIVE AND ABSOLUTE CONCENTRATIONS IN SEMI-INSULATING GAAS , 1998 .

[12]  W. Stadler,et al.  Defects in CdTe and Cd1−xZnxTe , 1996 .

[13]  P. Rudolph,et al.  Defects in CdTe bridgman monocrystals caused by nonstoichiometric growth conditions , 1993 .

[14]  J. G. Simmons,et al.  High-Field Isothermal Currents and Thermally Stimulated Currents in Insulators Having Discrete Trapping Levels , 1972 .

[15]  Timothy C. Hayes,et al.  Low Temperature Crystal Growth and Characterization of Cd 0.9 Zn 0.1 Te for Radiation Detection Applications , 2011 .

[16]  S. Kang,et al.  Crystal Growth and Characterization of CdTe and Cd 0.9 Zn 0.1 Te for Nuclear Radiation Detectors , 2007 .

[17]  R. James,et al.  Characterization of Low-Defect ${\rm Cd}_{0.9}{\rm Zn}_{0.1}{\rm Te}$ and CdTe Crystals for High-Performance Frisch Collar Detectors , 2007, IEEE Transactions on Nuclear Science.

[18]  Michael Groza,et al.  Simulation, modeling, and crystal growth of Cd0.9Zn0.1Te for nuclear spectrometers , 2006 .