Effect of doping and annealing on resistivity, mobility-lifetime product, and detector response of (Cd,Mn)Te

• Published in: Journal of alloys and compounds 2023-03, Vol.936, p.168280, Article 168280
• Main Authors: Wardak, Aneta, Kochanowska, Dominika M., Kochański, Michał, Dopierała, Marcin, Sulich, Adrian, Gdański, Janusz, Marciniak, Adam, Mycielski, Andrzej
• Format: Article
• Language: English
• Subjects: Compensation; Crystal growth; Detectors; Dopants; Semi-insulators; X-ray and gamma-ray spectroscopies
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2022.168280

We present the effect of doping with In, V, and Cl on the values of resistivity (ρ) and mobility-lifetime (μτ) in (Cd,Mn)Te crystals grown by the Bridgman method and with diameters of 2 or 3 in. This material is investigated to use in room-temperature X-ray and gamma-ray detectors. We carried out post-growth annealing processes in cadmium vapors at 500 °C to obtain more homogeneous crystal properties. The EU-ρ-μτ-SCAN machine, which uses the principle of time-dependent charge measurement, allowed us to map the values of resistivity and mobility-lifetime in crystal plates. High values of those two quantities are crucial in nuclear detector applications. Crystals doped with In show inhomogeneous properties, which makes the fabrication of competitive large-area crystals more difficult. Low-temperature post-growth annealing in Cd vapors is insufficient for (Cd,Mn)Te:In crystals, where the decrease of ρ and μτ values is observed. Such annealing works for (Cd,Mn)Te:V crystals, where the mean values of ρ and μτ do not change significantly, but their distributions are more uniform. Both dopants, vanadium and indium, used together with an excess of Te, effectively increased ρ and μτ. Using the 57Co source, the spectroscopic performance of each pixel of the detector co-doped with In and V was shown. •Indium causes an uneven distribution of resistivity in the crystal plates.•Annealing of (Cd,Mn)Te:V in Cd vapors unifies the crystal properties.•Annealing of (Cd,Mn)Te:In in Cd vapors reduces resistivity due to overcompensation.•Co-doping with In and V gives uniform crystal properties and spectroscopic response.