| This thesis is focused on the controlled growth and physical properties of Zn O films on the atomic scale, the formation and characteristics of the homogeneity and heterogeneity of core-shell nanostructures and Zn O light emitting device and photo detecting device. The following are the major results:1. Zn O films were deposited by atomic layer deposition, the influence of deposition temperature on the growth rate, crystal structure and optical properties of Zn O had been discussed. By difference doping methods, the photoelectric properties of Zn O had been adjusted. In addition, for the first time, Zn O and Al-doped Zn O were deposited PVP nanofibers’ surface, which was used the template, then, Zn O/ Al-doped Zn O homo core/ shell structure nanowires were formed. From the PL spectrum, we observed the TES emission, which caused the enhancement of UV emission.2. Using Si C and Ga N as stable p type semiconductors, through a facile low-temperature hydrothermal process, Zn O nanorod arrays were grown on Zn Mg O films/ p-Si C to form a heterojunction LED. Mg Zn O films were grown on p-Si C by a simple sol-gel method. In this heterojunction structure, Mg Zn O films works as the seeds film for the growth of Zn O nanorods. In particular, Mg Zn O films can work as barrier layer between n-Zn O nanorods and p-Si C, which controls the movement of holes and electrons. Thus, with this introduced Mg Zn O films, the electroluminescence(EL) from Zn O can be observed in Zn O/ Si C heterojunction. Under a forward bias larger than 18 V, the emission band in electroluminescence(EL) speactrum is considered as a combination of an peak centered at 388 nm and a yellow band emission peak around 450 nm. As the injection current increased, the intensity of ultraviolet emission was also increased. At last, the Zn O homo core/ shell structure nanowires were introduced in Ga N/Mg Zn O/Zn O structure, due to the influence of Al-doped Zn O shell layer, the electron carrier concentration were increased, compared with Ga N /Zn O structure, the intensity of EL emission were 50 times higher than Ga N /Zn O structure.3. The structural and optical properties of Zn O and Zn O/Zn S core–shell nanowires grown by a wet chemical method are investigated. The near-bandgap ultraviolet(UV) emission of the Zn O nanowires was enhanced by four times after coating with Zn S. The enhanced emission was attributed to surface passivation of the Zn O nanowires, and localized states introduced during Zn S growth. The emission of the Zn O and Zn O/Zn S core-shell nanowires was attributed to neutral donor-bound excitons and localized excitons, respectively. Localized states prevented excitons from diffusing to non-radiative recombination centers, so therefore contributed to the enhanced emission. Emission from the localized exciton was not sensitive to temperature, so emission from the Zn O/Zn S core-shell nanowires was more stable at higher temperature. UV photodetectors based on the Zn O and Zn O/Zn S core-shell nanowires were fabricated. Under UV excitation, the device based on the Zn O/Zn S core-shell nanowires exhibited a photocurrent approximately 40 times higher than that of the device based on the Zn O nanowires. The differing photoresponse of the detectors was consistent with the existence of surface passivation and localized states. This study provides a means for modifying the optical properties of Zn O materials, and demonstrates the potential of Zn O/Zn S core–shell nanowires in UV excitonic emission and detection. |
PDF Full Text Request