Cvd Preparation Of Zno Thin Films Synthesis And Characterization, Luminescence Properties Of Alkali Metal Titanate Nanowires

There has been a great deal of interest in ZnO semiconductor materials lately in part because of its large exciton binding energy (60 meV) which could lead to lasing action based on exciton recombination even above room temperature. The wide band gap semiconductor, wurtzite ZnO, has been studied widely due to its potential commercial applications such as short wavelength ultraviolet laser diodes, light emission diodes, transparent electrodes, gas sensors, surface acoustic wave devices and so on. It has some advantages over GaN because of its availability in high-quality bulk, single-crystal form and its larger exciton binding energy. For ZnO, n-type conductivity is relatively easy to realize via excess Zn or with Al, Ga, or In doping. Despite all the progress that has been made and the reports of p -type conductivity in ZnO films using various growth methods and various group-V dopant elements, a reliable and reproducible high- quality p -type conductivity has not yet been achieved for ZnO. The deposition of ZnO films by CVD has been attractive for a long time because of high growth rate, good surface flatness and preferred orientation. However, high cost, complicated ductwork, and assistant equipments such as plasma enhancing and electron cyclotron resonance are usually involved in most conventional atmospheric pressure CVD apparatus.The nature of the residual n-type conductivity in undoped ZnO films is still under some degree of debate. The well-known green band in ZnO PL spectra is related to singly ionized oxygen vacancies by some and to other defects or impurities by others. The transition of the donor- and acceptor- bound excitons and the donor-acceptor-pair (DAP) are still ambiguous in the low-temperature PL spectra of ultraviolet range. The major works and conclusions on...