tailieunhanh - Báo cáo hóa học: " Direct Synthesis and Characterization of Optically Transparent Conformal Zinc Oxide Nanocrystalline Thin Films by Rapid Thermal Plasma CVD"

Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí hóa hoc quốc tế đề tài : Direct Synthesis and Characterization of Optically Transparent Conformal Zinc Oxide Nanocrystalline Thin Films by Rapid Thermal Plasma CVD | Pedersen et al. Nanoscale Research Letters 2011 6 568 http content 6 1 568 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Direct Synthesis and Characterization of Optically Transparent Conformal Zinc Oxide Nanocrystalline Thin Films by Rapid Thermal Plasma CVD Joachim D Pedersen Heather J Esposito and Kwok Siong Teh Abstract We report a rapid self-catalyzed solid precursor-based thermal plasma chemical vapor deposition process for depositing a conformal nonporous and optically transparent nanocrystalline ZnO thin film at 130 Torr atm . Pure solid zinc is inductively heated and melted followed by ionization by thermal induction argon oxygen plasma to produce conformal nonporous nanocrystalline ZnO films at a growth rate of up to 50 nm min on amorphous and crystalline substrates including Si 100 fused quartz glass muscovite c- and a-plane sapphire Al2O3 gold titanium and polyimide. X-ray diffraction indicates the grains of as-deposited ZnO to be highly textured with the fastest growth occurring along the c-axis. The individual grains are observed to be faceted by 103 planes which are the slowest growth planes. ZnO nanocrystalline films of nominal thicknesses of 200 nm are deposited at substrate temperatures of 330 C and 160 C on metal ceramic substrates and polymer substrates respectively. In addition 20-nm- and 200-nm-thick films are also deposited on quartz substrates for optical characterization. At optical spectra above 375 nm the measured optical transmittance of a 200-nm-thick ZnO film is greater than 80 while that of a 20-nm-thick film is close to 100 . For a 200-nm-thick ZnO film with an average grain size of 100 nm a four-point probe measurement shows electrical conductivity of up to 910 S m. Annealing of 200-nm-thick ZnO films in 300 sccm pure argon at temperatures ranging from 750 C to 950 C at homologous temperatures between and alters the textures and morphologies of the thin film. .