Investigation of defect levels in Bi12SiO20 single crystals by thermally stimulated current measurements

Bi12SiO20 (BSO) single crystal belongs to the sillenite semiconducting family known as defective compounds. The present paper investigates the defect centers in BSO grown by Czochralski method by means of thermally stimulated current (TSC) measurements performed in the 10-260 K range. The TSC glow curve obtained at heating rate of β = 0.1 K/s presented several peaks associated with intrinsic defect centers. The activation energies of defect centers were revealed as 0.09, 0.15, 0.18, 0.22, 0.34, 0.70 and 0.82 eV accomplishing the curve fit analyses method. The peak maximum temperatures and orders of kinetics of each deconvoluted peak were also determined as an outcome of fitting process. TSC experiments were expanded by making the measurements at various heating rates between 0.1 and 0.3 K/s to get information about the heating rate dependent peak parameters.

Localized Deep and Shallow Traps of α-Peaks from Thermally Stimulated Current (TSC) Measurement on Thermoplastic Polymers

In this paper, trap levels around the glass transition temperature (Tg) of polymers have been characterized using Thermally Stimulated Current (TSC) technique. Deconvolution on α-peaks of the Tg for PE (-104 °C), plasticized PVC (-35 °C), PMMA (90 °C) and PET (96 °C) were carried out based on the first-order kinetic theory for non-Debye relaxation. Using temperature, T from TSC experimental data, we have successfully separated the α-peaks of the thermoplastic polymers. It is found that the complex curve of α-peaks can composed of four (4) to eight (8) sub peaks. Dominant sub peaks were identified at Tmax = -105 °C, -34 °C, 89 °C and 92 °C for PE, pPVC, PMMA and PET, respectively. These peaks show activation energy, Ea of shallow and deep trap centers ranged from 0.3 eV to 4.6 Ev where they represent the depolarization of localized dipoles and space charges relaxations in the polymers.

ASSESSMENT OF ELECTRICALLY ACTIVE DEFECT PARAMETERS IN POLYARYLENPHTHALIDES

Trapping state parameters in thin films of polyarylenephthalide polymers with different chemical structures were studied using the thermally stimulated current (TSC) method. As the objects of our research we used polyarylenephthalide polymers - polydiphenylphthalide (PDP) [1] and phthalide-based statistical co-polyarylene ether ketones (co-PAEK) [2]. It was revealed in the paper that the energy of trapping state activation essentially depends on the concentration of phhalide-containing fragments.