ZnO Thin Films And ZnO Ultraviolet Detector

Zinc Oxide is a material that has many applications. Traditionally, ZnO is used in acoustic wave devices (SAW), bulk acoustic devices (BAW), Gas sensors, varistors, transparent electrodes and so on. In recent years, ZnO, as a wide band semiconductor, has gained more and more attention. Compared with GaN, the most successful wide-band semiconductor material at present, ZnO has many promising advantages: high-quality ZnO with very low defect densities can be synthesized at relatively low temperature; ZnO has large excitonic binding energy (60mev at RT), which promises strong photoluminescence from bound excitonic emissions at room temperature; meanwhile, homogeneous ZnO substrate is available.The State Key Lab of Silicon Materials is one of the earliest groups in China that devote themselves to investigating on ZnO thin films. Under the guidance of Prof. Zhizhen Ye, our group deposit highly c-oriented ZnO thin films on silicon substrate by DC reactive magnetron sputtering (DCRMS) and focus on exploring the growth mechanism of nano-hexagonal structure of ZnO films. Our group first reported the strong photoluminescence of ZnO films deposited on Si substrate at room temperature by DCRMS and this research is well ahead of others in China.In this paper, the application and principles of various ZnO growth techniques are illustrated, and the up-to-date researching progress is reported. Highly C oriented thin films are synthesized by DC Reactive Magnetron Sputtering. The structure and properties are characterized by XRD, TEM, AFM, SRP, Absorption Spectra and Hall. The effects of sputtering coefficients such as sputtering power, substrate temperature, sputtering gas composition and pressure on the fimls' quality are clarified. The annealing's effects on ZnO's surface morphology, internal stress and defects are also investigated, and the definite mechanism is proposed, p-type ZnO is obtained by introducing NHa into to sputtering gas.As initial trial, MSM ZnO UV detectors are fabricated with ZnO thin films on Si substrate by PLD technique. Testing indicated that Metal Al and ZnO could form ohm contact easily and phtoresponsivity of 0.5A/W is achieved with 5V bias voltage.