| Summary: | 碩士 === 南臺科技大學 === 電子工程系 === 106 === In this study, the MgZnO thin films with various Mg contents were deposited on the quartz substrate by RF magnetron sputtering. The electrical and optical properties of the metal-semicoductor-metal ultraviolet (UV) photodetectors by different annealing treatments were investigated. After annealing, the properties of MgZnO thin films were characterized by SEM, XRD, and XPS.
There are two stages in our experiment: the first stage is the properties MgZnO thin films with 10% and 20% magnesium contents were deposited and analyzed. At an annealing temperature of 700 °C, the MgZnO thin film photodetectors with magnesium contents of 10% and 20% have lower dark currents and better responsivities. It can be found out that the oxygen vacancies decrease as the annealing temperatures increase by the XPS analysis of the magnesium and Zinc binding energy.
In the second stage, the dual-band photodetectors were fabricated by the stacks of the MgZnO thin films with the magnesium content of 10% and 20%. On the other hand, this is attributed to the deterioration of the film quality affected by the diffusion of magnesium atoms. Therefore, the SiO2 insulating layer was inserted between two MgZnO thin film layers to prevent the magnesium atoms diffusion at the high temperature annealing. In the responsivity of the fabricated dual-band photodetectors, the two peaks of the response wavelengths can be achieved at 300 nm and 350 nm by voltage bias adjustment.
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