Morphology-dependent space charge polarization and dielectric relaxation of CdO nanomorphotypes

• Main Authors: Paulose Thomas, K. E. Abraham
• Format: Article
• Language: English
• Published: World Scientific Publishing 2016-12-01
• Series: Journal of Advanced Dielectrics
• Subjects: CdO nanomorphotype; space charge polarization; impedance spectroscopy; Cole–Cole dielectric relaxation
• Online Access: http://www.worldscientific.com/doi/pdf/10.1142/S2010135X16500302
• ISSN: 2010-135X; 2010-1368

A versatile approach signifying the morphology-dependent dielectric polarization and relaxation mechanisms of cadmium oxide (CdO) nanosphere, nanoflakes and nanoparallelepiped morphotypes as a function of frequency and temperature is presented. Variation of dielectric property is observed due to the changes of space charge/interfacial polarization resulting from the variations of surface to volume ratio of nanomorphology. Accordingly, colossal dielectric constant value has been observed in CdO nanosphere having larger surface to volume ratio. The order of dielectric constant (dc) values observed for the present nanomorphologies is: dc of sphere > dc of flakes > dc of parallelepiped resembles the order of surface to volume ratios of the present morphologies respectively. The experimental data of complex impedance values are numerically fitted using theoretical models which provide the information of role of grain resistance on dielectric polarization and Cole–Cole type mechanism of dielectric relaxation process. The activation energies for electron transport are found to be 0.087eV for spheres, 0.074eV for flakes and 0.067 for parallelepiped nanomorphotypes of CdO. The dielectric and impedance spectroscopic analysis of the present material opens up wide scope for morphology-dependent tuning of nanomaterials for electrical applications.