Diode production by evaporating si̇lver wi̇th cold substrate method on zi̇nc oxi̇de thin films grown vi̇a spray-pyrolysi̇s method and characterization

In this thesis, ZnO thin films which commonly used in photoelectronic technologies were grown on SnO2/glass substrates by chemical spraying method at 325 °C substrate temperature. The film growth rate was set to 60 Å per minute by keeping the spray rate at 5 ml/min. During 30 min spraying, the ZnO films were allowed to grow at thickness of about 1.8-2.1 μm. Then the obtained ZnO films were annealed in the room environment at 350 °C, 375 °C and 400 °C for 30 minutes. Measurement were made on four different samples. X-ray diffraction patterns showed that all samples grew in hexagonal crystal structure. In addition, it was determined that the samples produced by different annealing temperatures had n-type electrical permeability. It was determined from the SEM images that the samples which were annealed and not annealed at different temperatures were in mikrorod form and underwent a structural transformation under the effect of temperature. It was observed that the energy band gaps calculated from the optical transmission spectra of the samples varied between 3.03 eV-3.03 eV. From the photoluminescence measurements, defects in the crystal structure of ZnO films were detected. However, the comparison of the ratios of the photoemission spectra of the sample revealed that sample which annealed at 375 °C was more impeccable than the other samples. In the second step of the study, Samples were divided into two groups and Ag/ZnO/SnO2 binary structures were obtained by evaporation of silver on ZnO surfaces at 300K and 200K substrate temperatures. For the formation of Schottky diodes, the first group of Ag/ZnO/SnO2 dual structures which produced at 300 K substrate temperatures, were annealed for 30 minutes at 400 °C, the second group of binary structures which produced at 200 K put substrate temperature, has been excited with rays by putting it under Ultraviolet rays at 354 nm wavelength for 1 hour. Ideality factors, barrier height and saturation current of the produced Schottky diodes, were determined.