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Mott–Schottky analysis of flower‐like ZnO microstructures with constant phase element behavior
Author(s) -
Allagui Anis,
Alawadhi Hussain,
Alkaaby Mustafa,
Gaidi Mounir,
Mostafa Khalid,
Abdulaziz Yacoub
Publication year - 2016
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201532509
Subject(s) - materials science , wurtzite crystal structure , constant phase element , capacitance , raman spectroscopy , dielectric spectroscopy , semiconductor , analytical chemistry (journal) , condensed matter physics , optoelectronics , electrochemistry , optics , chemistry , metallurgy , zinc , physics , electrode , chromatography
ZnO was prepared using room temperature bipolar electrochemical process in deionized water. Electron microscopy, powder X‐ray diffraction, and micro‐Raman spectroscopy showed crystallization of the material into the wurtzite hexagonal structure of ZnO, self‐organized in micro‐sized flower‐like shapes that are formed out of individual nanorods preferentially grown along the < 0 0 0 1 > direction. The intrinsic electronic properties were evaluated by potentiodynamic electrochemical impedance spectroscopy using Mott–Schottky analysis of semiconductor/liquid junctions. Because the flat band and carrier density are frequency‐dependent, we used an approximation based on fractional order capacitance fitting, and subsequently three different ways to calculate the frequency‐independent effective capacitance of the system. The capacitance computed using the four parameters of single‐dispersion Randle's model, i.e., pseudocapacitance, dispersion coefficient, and series and parallel resistances, is more recommended for the characterization of the electrochemical system.