Role of defects in the photomagnetoconductivity and photoluminescence properties of ZnO microwires

C. I. ZANDALAZINI; M. VILLAFUERTE; I. LORITE; P. ESQUINAZI; S. PEREZ DE HELUANI

Bariloche

Conferencia; Advanced Topics in Magnetism and Superconductivity AToMS-2014; 2014

CAB-CNEA

We present experiments to systematically study the characteristic times involved in the spin dependent recombination processes in ZnO doped semiconductors. Undoped and Li-doped (3, 5 and 7%) ZnO microwires were prepared by carbothermal reduction process and then co-doped with H using two different times of H+ implantation. The results of photoluminescence showed that the Li concentration is directly linked to the emission intensity of the samples at 3.14 eV, reaching its maximum for 5% of Li. The characterizations were performed using the techniques of X-ray diffraction, photoluminescence (PL), photoresistance (PR), and photomagnetotransport (PMT). The samples showed high resistivity and persistent photoconductivity. In order to prevent inconsistencies and/or lack of reproducibility, product of the history of the samples, a novel methodology to measure the photoresistance(PR) transient relaxation is proposed. Besides, the PR excitation spectra as a function of the wavelength of light showed that the change in PR in the blue region is more marked for 7% of Li. Different models were used to fit the significant effect of the applied magnetic field on photocurrent decay. Our results suggest that a spin-dependent, non-radiative recombination process is responsible for photoresistivity changes in Li and H co-doped ZnO microwires.