Effect of post deposition annealing on thermal evaporated ZnSe:Te towards a scintillator application

• Comparatively inexpensive method to realize ZnSe:Te scintillating film.
• Annealing on the deposited film.
• Effect of annealing on crystallinity of the deposited films.
• Effect of annealing on optical and electronic properties of the deposited film.

ZnSe having a wide but direct bandgap (bulk band gap 2.7 eV) is very efficient for detecting nuclear radiations by using its scintillation property. With a high absolute light output and radiation spectra which match well with Si-photodiode spectral sensitivity, ZnSe scintillators have adequately minimized the gap between “scintillator-photodiode” series for modern radiation detectors. Promising features like long decay time and high values of intrinsic radiation absorption make ZnSe based scintillators a very interesting research filed. Here in this report, we investigate an inexpensive and easy method to realize ZnSe:Te film on a quartz substrate. ZnSe:Te film is deposited using a thermal evaporator using ZnSe and ZnTe powders as raw materials to start with. After the deposition, the samples are exposed to a thermal annealing step for 1 h. The temperatures are kept at 624, 674 and 724 K. We have confirmed presence of a preferred [1 1 1] oriented polycrystalline ZnSe:Te thin films by XRD experiments. Photoluminescence experiment using a He:Cd laser at 324 nm at low temperature (8 K) reports an emission at 2.54 eV due to non-equilibrium carrier plasma.

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