Özet:

The aim of this study is to investigate the influences of annealing temperature on initial device characteristics and their correlations with ultraviolet (UV) radiation sensitivity of n-type zinc oxide/p-silicon (n-ZnO/p-Si) heterojunction photodiodes. Evolutions on the crystalline structure, surface morphology, ideality factor, barrier potential, interface state density, and donor concentration were systematically analyzed during the initial device characterizations before testing the UV sensitivities of the photonic devices. The results demonstrate that the sensitivity of each n-ZnO/p-Si photodiode annealed at various temperatures was linearly correlated with different UV illumination intensities. The devices annealed at 750 ºC and 550 ºC exhibit more sensitive performance than devices annealed at 150 ºC and 350 ºC owing to lower dark currents and good oxide quality. However, the presence of an interfacial suboxide or silicate oxide layer significantly decreased the responsivity of the photodiodes annealed at 750 ºC. The maximum responsivity value was 126 mA/W for the photodiode annealed at 550 ºC. It can be concluded that the photodiode annealed at 550 ºC exhibits promising performance for UV sensing applications.

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