Characterization of ZnMgO hexagonal-nanotowers/films onm-plane sapphire synthesized by metal organic chemical vapour deposition

Abstract

ZnMgO hexagonal-nanotowers/films grown on m-plane sapphire substrates were successfully synthesized using a vertical low-pressure metal organic chemical vapour deposition system. The structural and optical properties of the as-obtained products were characterized using various techniques. They were grown along the non-polar direction and possessed wurtzite structure. The ZnMgO hexagonal-nanotowers were about 200 nm in diameter at the bottom and 120 nm in length. Photoluminescence and Raman spectra show that the products have good crystal quality with few oxygen vacancies. With Mg incorporation, multiple-phonon scattering becomes weak and broad, and the intensities of all observed vibrational modes decrease. The ultraviolet near band edge emission shows a clear blueshift (as much as 100 meV) and broadening compared with that of pure ZnO products.

The effect of different oriented sapphire substrates on the growth of polar and non-polar ZnMgO by MOCVD

“…1 (i)-(l). However, when the growth condition changed, for example, increasing the VI/II mole ratio and reaction time, the Zn 1 À x Mg x O hexagonal-nanotowers tilted by 301 from the normal of the M-plane surface were formed, as was reported by our previous work [21]. Fig.…”

Measurement of polar C-plane and nonpolar A-plane InN/ZnO heterojunctions band offsets by x-ray photoelectron spectroscopy

“…Also, the VBO of the C-plane Table I. heterojunction is very close to the value ͑1.95eV͒ that was predicted by Veal et al 20 Using the room temperature band gaps for ZnO and InN ͑3.3 13,14 and 0.7 eV, 1 respectively͒, the InN/ZnO heterojunctions are found to have a type-I ͑staggered͒ band lineup, as shown in Fig. 3, with corresponding conduction band offsets ͑CBOs͒ of 0.84Ϯ 0.2 eV and 0.40Ϯ 0.2 eV for C-plane and A-plane heterojunctions.…”

“…The C-plane and A-plane ZnO in this study were grown by low-pressure metal-organic chemical vapor deposition ͑MOCVD͒, as described elsewhere. 13,14 The C-plane and A-plane InN was grown at 520°C by atmospheric pressure MOCVD. 9 The crystal structures and epitaxial relationships were characterized using a Philips X'Pert x-ray diffraction ͑XRD͒ apparatus and high-resolution XRD measurements ͑Beijing Synchrotron Radiation Facility, not shown here͒.…”

A Review on Less-common Nanostructures

“…[160] In another zinc-containing product, the ZnMgO hexagonal nanotowers were about 200 nm in diameter at the bottom and 120 nm in length. [161] The CO oxidation reaction was studied using a controlled structure consisting of Au/CeO 2 multilayers, in the form of towers of 10x10 µm 2 11. Nanochain (SiO x ).…”