Distribution of zinc, resistivity, and photosensitivity in a vertical Bridgman grown Cd1−xZnxTe ingot

Abstract

We present the results of a comprehensive study of distribution of zinc, resistivity, and photosensitivity in a Cdl,Zn,Te ingot grown by the Vertical Bridgman method. We used several complementary methods, viz., glow discharge mass spectroscopy, photoluminescence-, resistivity-, and photosensitivity-mapping, along with photo-induced current transient spectroscopy to characterize the material. We identified electronic levels in the band-gap responsible for compensation, recombination, and photosensitivity.

Anomalous segregation during electrodynamic gradient freeze growth of cadmium zinc telluride

“…35, thus leading to segregation during growth and non-uniform composition. Zinc uniformity is important for detector-grade material, since it strongly affects electrical resistivity [10].…”

Compensation and trapping in large bandgap semiconductors: Tuning of the defect system in CdZnTe

“…We demonstrated previously [3,11,12] that a small variation of the deep-donor level position with respect to the Fermi level can raise electron trapping by approximately 5-10 times.…”

“…All wafers demonstrated a small variation of the Zn content over the longest dimension. Details of experimental measurements were described elsewhere [3].…”

“…This dearth of information creates formidable technological-and modeling-difficulties when a small concentration of defects with deep energy levels controls the semiconductor's basic properties, such as compensation, trapping, and polarization [2,3]. Most techniques that are used for identifying defects cannot generate reliable data about them; this introduces uncertainty about what parameters can be controlled during crystal growth.…”

Characterization of compensation and trapping in CdTe and CdZnTe: Recent advances

“…This figure is far above the residual concentration of impurities in Ge and Si, wherein concentrations of about 10 10 cm -3 routinely are achievable [21]. The complex structure of native defects in binary semiconductors, and especially in ternary ones compounds the problem of experimentally characterizing these materials [22][23][24][25][26][27]. It is practically impossible to precisely and simultaneously assess the concentration of impurities and native defects, their ionization energies, and their chemical composition.…”