Study of electric conduction mechanisms in bismuth silicate nanofibers

Abstract

This work represents the nature of conduction mechanism in bismuth silicate (BiSiO) nanofibers as a function of temperature and frequency. Scanning electron micrographs and X-rays diffraction patterns exhibited the formation of cubic phases of Bi 4 (Sio 4 ) 3 and Bi 12 Sio 20 nanofibers respectively with an average diameter of ~200 nm. Temperature dependent (300 K-400 K) electrical characterization of fibers was carried out in frequency range of ~20 Hz-2 MHz. The complex impedance analysis showed contribution from bulk and intergranular parts of nanofibers in conduction. Moreover, analysis of the Cole-Cole plot confirmed the space charge dependent behavior of BiSiO nanofibers. Two types of relaxation phenomena were observed through Modulus analysis. In ac conductivity curve, step like feature of plateau and dispersive regions were described by Maxwell-Wagner effect while the dc part obeyed the Arrhenius law. However, frequency dependent ac conductivity revealed the presence of conduction mechanism in diverse regions that was ascribed to large polaron tunneling model. Detailed analysis of complex Impedance and ac conductivity measurement showed negative temperature coefficient of resistance for the BiSiO nanofibers. Current-voltage (IV) characteristics represented ohmic conduction; followed by space charge limited current conduction at intermediate voltages. Results from both ac and dc measurements were in good agreement with each other.

The electrical behaviour of ultrafine bismuth phosphate particles under a range of temperature and frequency conditions

“…A similar type of behaviour has been reported for bismuth-based ceramic glasses. 52,53 The variation of AC conductivity as a function of temperature was analysed using Jonscher's universal power law, σ AC = σ DC + A ( T ) ω S …, where A is the temperature-dependent factor associated with the polarizability strength of the material and ‘ S ’ is the frequency-dependent parameter, which varies between 0 and 1. The parameter ‘ S ’ has been used to determine the conductivity mechanism.…”

“…A similar type of behaviour has been reported for bismuth-based ceramic glasses. 52,53 The variation of AC conductivity as a function of temperature was analysed using Jonscher's universal power law,…”

Crystal Interface Control at Low Thermal Gradient and Investigation of the Effect of Cr on the Crystal Structure and Optical Properties of Bismuth Silicate

“…[ 6–14 ] It is used for two‐wave mixing, four‐wave mixing, phase conjugation, real‐time holography, optical data storage, optical computing, and electro‐optical modulation. [ 7,8 ]…”

“…[1][2][3][4][5] Among sillenites, bismuth silicate (Bi 12 SiO 20 , BSO) is a technologically important material as it exhibits large electro-optic and photoconductive effects, which make it suitable for optical switches, optics-based electric field sensors, holographic storage, and photorefractive devices. [6][7][8][9][10][11][12][13][14] It is used for two-wave mixing, four-wave mixing, phase conjugation, real-time holography, optical data storage, optical computing, and electro-optical modulation. [7,8] It has been reported that the photorefractive property of BSO is enhanced significantly on doping with metals like Cr, Fe, Mg, Ru, etc.…”

“…[6][7][8][9][10][11][12][13][14] It is used for two-wave mixing, four-wave mixing, phase conjugation, real-time holography, optical data storage, optical computing, and electro-optical modulation. [7,8] It has been reported that the photorefractive property of BSO is enhanced significantly on doping with metals like Cr, Fe, Mg, Ru, etc. [8,[15][16][17][18][19][20][21][22][23][24][25][26][27] Though most of these dopants make material sensitive to photorefraction in the visible region, especially around 500 nm, that is, 2.5 eV, practical feasibility prefers the region near the infrared (1.5À2 eV), mainly because of the availability of compact laser diodes in this region.…”