RESUMEN
Low-energy cathodoluminescence (CL) imaging and spectroscopy technique was employed to study the impurity distribution in individual ZnO hexagonal nanotubes fabricated by metalorganic chemical vapor deposition on the sapphire (0001) substrate. The CL spectra at 10 K show that acceptor and donor impurities are incorporated in the ZnO nanotubes. CL monochromatic images indicate that the concentration of donor is higher at the bottom part and the distribution of acceptors is more inhomogeneous at the surface of the nanotubes. The non-uniform defects and impurities distributions are explained by unstable growth conditions and contamination from the environment. These results indicate that the low-energy CL is a very powerful method to investigate the inhomogeneity of luminescence properties in the individual nanostructures.
Asunto(s)
Nanopartículas del Metal/química , Nanotecnología/métodos , Óxido de Zinc/química , Óxido de Aluminio , Química Orgánica/métodos , Electrodos , Electrones , Luminiscencia , Microscopía Electrónica de Rastreo , Nanopartículas/química , Nanoestructuras/química , Nanotubos , Nanotubos de Carbono/química , Fotones , TemperaturaRESUMEN
Between February 1989 and April 1993, 46 patients with thyroid adenoma were treated by electrochemical treatment (ECT) during acupuncture anaesthesia. After three months to four years follow up period, the cure rate was 97.8%. ECT is a new technique which provides simple, effective and safe treatment of thyroid adenoma. Treatment of benign tumours with ECT represents a new application.