Open AccessChemical composition tuning induced variable and enhanced dielectric properties of polycrystalline Ga 2‐2 x W x O 3 ceramics
Author(s) -
Zade Vishal B.,
Rajkumar Mohan R.,
Broner Ron,
Ramana Chintalapalle V.
Publication year - 2021
Publication title -
engineering reports
Language(s) - English
Resource type - Journals
ISSN - 2577-8196
DOI - 10.1002/eng2.12300
Subject(s) - dielectric , materials science , analytical chemistry (journal) , crystallite , polaron , dissipation factor , dielectric loss , relaxation (psychology) , activation energy , electrical resistivity and conductivity , gallium , chemistry , optoelectronics , electrical engineering , organic chemistry , physics , psychology , social psychology , quantum mechanics , metallurgy , engineering , electron
Abstract We report on the tunable and enhanced dielectric properties of tungsten (W) incorporated gallium oxide (Ga 2 O 3 ) polycrystalline electroceramics for energy and power electronic device applications. The W‐incorporated Ga 2 O 3 (Ga 2−2x W x O 3 , 0.00 ≤ x ≤ 0.20; GWO) compounds were synthesized by the high‐temperature solid‐state chemical reaction method by varying the W‐content. The fundamental aspects of the dielectric properties in correlation with the crystal structure, phase, and microstructure of the GWO polycrystalline compounds has been investigated in detail. A detailed study performed ascertains the W‐induced changes in the dielectric constant, loss tangent (tan δ ) and ac conductivity. It was found that the dielectric constant increases with addition of W in the system as a function of temperature (25°C‐500°C). Frequency dependence (10 2 ‐10 6 Hz) of the dielectric constant follows the modified Debye model with a relaxation time of ∼20 to 90 μs and a spreading factor of 0.39 to 0.65. The dielectric constant of GWO is temperature independent almost until ∼300°C, and then increases rapidly in the range of 300°C to 500°C. W‐induced enhancement in the dielectric constant of GWO is fully evident in the frequency and temperature dependent dielectric studies. The frequency and temperature dependent tan δ reveals the typical behavior of relaxation loses in GWO. Small polaron hopping mechanism is evident in the frequency dependent electrical transport properties of GWO. The remarkable effect of W‐incorporation on the dielectric and electrical transport properties of Ga 2 O 3 is explained by a two‐layer heterogeneous model consisting of thick grains separated by very thin grain boundaries along with the formation of a Ga 2 O 3 ‐WO 3 composite was able to account for the observed temperature and frequency dependent electrical properties in GWO. The results demonstrate that the structure, electrical and dielectric properties can be tailored by tuning W‐content in the GWO compounds.