Growth and characterization of detector-grade CdMnTe by the vertical Bridgman technique

U N Roy,O K Okobiah,R Gul,S U Egarievwe,G S Camarda,R B James,G Yang,A Hossain,Y Cui

doi:10.1063/1.5040362

Abstract

We grew Cd1-xMnxTe crystals with a nominal Mn concentration of 5% by the vertical Bridgman growth technique. The compositional variation along the length of the grown ingot was studied by powder X-ray diffraction. The composition was found to be uniform along the growth direction. The achieved resistivity was 1-2.5 x1010 ohm-cm with a mobility-lifetime (μτ) product value for electrons of ∼1.7x10-3 cm2/V. An energy resolution of ∼7.5% at 662 keV was achieved for a 9-mm long Frisch grid detector fabricated from an ingot grown using as-received starting materials.

Highlights

Cd1-xMnxTe (CMT) is a ternary II-VI material and can be grown with a zinc-blende structure for up to 77% Mn concentration.[1]
It is to be noted that, even for the CMT crystals grown with 6N purity Mn as starting material, the value of the reported μτ product was around 10-4 cm2/V.13
In this paper we report on the growth of indium-doped CMT crystals by the vertical Bridgman technique using Mn (99.9998%), 6N purity Te from Alfa Aesar and 6N purity CdTe from 5N Plus, Inc. as the starting materials

Summary

INTRODUCTION

Cd1-xMnxTe (CMT) is a ternary II-VI material and can be grown with a zinc-blende structure for up to 77% Mn concentration.[1]. An energy-resolution of 2.1% at 662 keV was demonstrated with a Frisch grid detector with dimensions of 5x5x12 mm[3] fabricated from Bridgman-grown CMT after purification of the starting MnTe by zone refining with molten tellurium for two cycles.[15] Recently Wen et al.[16] reported the charge-transport characteristics for THM-grown CdMnTe and obtained a μτ value up to 1.45x10-3 cm2/V. These results are very encouraging and make CMT an attractive alternate room-temperature semiconductor material to CZT. We report for the first time on the detection of 662-keV gamma-rays using a Frisch grid detector geometry fabricated from a Bridgman-grown CMT crystal produced from as-received starting materials

EXPERIMENTAL

RESULTS AND DISCUSSION

SUMMARY