The preparation of cesium-iodide thin films via sol–gel method for the detection of ionizing radiation

Abstract

Thin film of CsI was deposited on glass substrate using the sol–gel technique. The different surface morphology of sol–gel films with respect to evaporated films can be assumed as the main cause of the more QE (quantum efficiency) of sol–gel CsI films. The thin films were characterized by scanning electron microscopy, Atomic force microscopy and X-ray diffraction, and optical properties were followed by optical absorption and UV–vis fluorescence. Also, thin films and bulk samples were studied by fluorescence spectroscopy. The increased contribution of emission spectrum of the nanocrystal in thin film samples in comparison with bulk was observed. In thin films, nanocrystals are more closely in contact with the network and this affects the luminescence features. So the energy transfer from the matrix to nanocrystals, which is a key characteristic for scintillation detectors, was investigated in the two systems. Scintillation tests were performed on the CsI thin film and bulk sample by photo multiplier tube-based material exposed to alpha irradiation.

Graphical Abstract

Thin film of CsI was deposited on glass substrate using the sol–gel technique. The increased contribution of emission spectrum of the nanocrystal in thin film samples in comparison with bulk was observed. Also, the energy transfer from the matrix to nanocrystals, which is a key characteristic for scintillation detectors, was investigated in the two systems. Figure 3 shows the SEM image of CsI thin film. SEM studies shows that the particles are distributed uniformly and mostly of homogeneous morphology at high magnification. SEM image of CsI thin film with the molar ratio about 10:1 for EtOH:TEOS and nine times deposited at magnification 100 kx.