Chlorine-doped ZnO thin films prepared by electrodeposition

MICAELA CAMINO; MARIANA BERRUET; MARCELA VAZQUEZ

Joao Pessoa

Encuentro; XIII Brazilian MRS Meeting; 2014

SBPMat

ZnO is a semiconductor with a wide range of properties depending on its structure, morphology and conductivity. Among these properties, the transparency in the visible region is assured by its wide band gap (3.3 eV for intrinsic ZnO), and its conductivity can be tuned by controlling the carrier´s concentration (doping level). The purpose of this work is to electrodeposit transparent and highly conductive n-type ZnO thin films doped with chloride, using conductive glass as substrate. The reaction mechanism that governs ZnO formation and morphology is strongly dependent on the electrochemically active precursors. Two different agents such as oxygen or nitrate ions were employed and compared. UV- Vis spectra were recorded to evaluate the transparency. Using nitrate as precursor, ZnO showed light scattering in visible range. To analyze the effect of chloride ions present in the electrolytic bath, KCl solutions were progressively added in concentrations from 0 to 0.2 mol L-1. Preliminary results showed shifting in absorption edges by Burstein-Moss effect. Electrical properties such as charge carrier density (N) and thin film resistivity () were analyzed by EIS and van der Paw method, respectively. As expected, N increases and  decreases in chloride doped films. The morphology, thickness, crystalline structure and chemical composition of ZnO films were analyzed and compared by SEM, XRD, Raman spectroscopy and EDX, respectively.