Fabrication of well-aligned ZnO nanorods by hydrothermal process using GaN epitaxial layer

摘要

One dimensional (1-D) ZnO nanorod structure of hexagonal shape was fabricated on epitaxial GaN layer by hydro-thermal method. The growth of GaN epitaxial layer was carried out in a two-flow horizontal MOCVD reactor maintained at a pressure of 200 torr. Firstly, a 25 nm thick GaN buffer layer was grown at 520℃. Then 2 ～ 3μ m thick GaN epilayer was deposited at 1070℃. Trimethylgallium (TMG) and NH_3 were used as Ga and N source, and H_2 gas was used as carrier gas. After the deposition of GaN epilayer thin-film, single crystalline ZnO nanorod was fabricated in aqueous solution. XRD and FE-SEM results showed ZnO nanorod arrays were oriented highly along the (002) plane. The ZnO nanorod was analyzed to have good quality crystallization by FE-TEM. The SAED pattern has shown that ZnO nanorod was grown in the direction along (002)-plane. Photoluminescence (PL) has shown that the GaN-ZnO hetero-structure has shown ultra-violet lasing action at room temperature. Narrow and strong ultra-violet peak was observed in comparison with PL result from epitaxial GaN layer. The analysis results have proved that aqueous solution growth method developed in the present work can be a good application for optical electronic device.