Phenomenological Characterization Of Photoactive Centers In Undoped Bi12tio20 Crystals Using Optical And Electrical Techniques

We report optical and electrical measurements contributing for a better characterization of the relevant photoactive center levels in undoped photorefractive Bi12TiO20 (BTO) crystals grown in Brazil. A center responsible for photochromism was identified at about 0.42eV, probably below the conduction band (CB). Two other defect centers were clearly identified at 0.17 eV and at 0.60 eV. Different centers between 1.0 and 0.85, probably above the valence band (VB), were mesured using different techniques which probably correspond to the same electron-acceptor de{reversed not sign}fect responsible for dark p-conductivity which was already reported in the literature. Classical photoconductivity experiments indicated electron-donor centers at least at about 2.2 and 2.5 eV. Holographic techniques indicated the presence of at least two photoactive centers closer than 1.6 eV from CB, one of which could be an empty one. © 2005 OSA/PEMD 2005.221227Grabmaier, B., Oberschmid, R., Properties of Pure and Doped Bi12GeO20 and Bi12SiO20 Crys{reversed not sign}tals. (1986) Phys. Stat. Sol, 96, pp. 199-211Kamshilin, A.A., Petrov, M.P., Continuous reconstruction of holographic interferograms through anisotropic diffraction in photorefractive crystals (1985) Opt. Commun, 53, pp. 23-26Mallick, S., Rouede, D., Influence of the polarization Direction on the Two-Beam Coupling in Photorefractive Bii2SiO20: Diffusion Regime (1987) Appl. Phys. B, 43, pp. 239-245Mosquera, L., de Oliveira, I., Frejlich, J., Hernandes, A., Lanfredi, S., Carvalho, J., Dark conductivity, photoconductivity and light-induced absorption in photorefractive sillenite crystals. (2001) J. Appl. Phys, 90, pp. 2635-2641Marinova, V., Lin, S., Sainov, V., Gospodinov, M., Hsu, K., Light-induced properties of Ru-doped Bii2TiO20 crystals (2003) J. Opt. A: Pure Appl. Opt, 5, pp. S500-S506Odoulov, S.G., Shcherbin, K.V., Shumeljuk, A.N., Photorefractive recording in BTO in the near infrared (1994) J. Opt. Soc. Am. B, 11, pp. 1780-1785Dos Santos, T., Carvalho, J., Hernandes, A., Synthesis and crystal growth of sillenite phases in the Bi203-Ti02-Nb205 system (2004) Crys. Res. Technol, 39, pp. 868-872Buse, K., Light-induced charge transport processes in photorefractive crystals I: Models and experi{reversed not sign}mental methods (1997) Appl. Phys. B, 64, pp. 273-291Aldrich, R., Hou, S., Harvill, M., Electrical and Optical Properties of Bi12Si02o (1971) J-Appl. Phys, 42, pp. 493-494Baquedano, J.A., Contreras, L., Dieguez, E., Cabrera, J., Spectral dependence of photorefractive erasure in Bi12Ge02o and Bi12Si02o (1989) J-Appl. Phys, 66, pp. 5146-5150Delboulbe, A., Fromont, C., Herriau, J., Mallick, S., Huignard, J., Quasi-nondestructive readout of holographically stores information in photorefractive Bi12Si02o crystals (1989) Appl. Phys. Lett, 55, pp. 713-715Riehemann, S., Rickermann, F., Volkov, V., Egorysheva, A., von Bally, G., Optical and photore{reversed not sign}fractive characterization of BTO crystals doped with Cd, Ca, Ga and V. (1997) J. Nonlinear Opt. Phys. and Materials, 6, pp. 235-249Longeaud, C., Kleider, J., General analysis of the modulated-photocurrent experiment including the contributions of holes and electrons (1992) Phys. Rev. B, 45, pp. 11672-11684Longeaud, C., Kleider, J., Kaminski, P., Koslowski, R., Pawlowski, M., Cwirko, R., Investigation of defect levels in semi-insulating materials by modulated and transient photocurrent: comparison of methods (1999) Semiconductor Science Technology, 14, p. 74