Production and characterization of MoSe 2 nanotubes by electron irradiation D. H. Galván, R. Rangel 1 and E. Adem 2 Centro de Ciencias de la Materia Condensada-UNAM, Apartado Postal 2681, C. P. 22800, Ensenada, B. C., México. 1 Escuela de Ingeniería Química, Universidad Michoacana de S. N. H., Edificio"K", Ciudad Universitaria, C. P. 58060, Morelia, Michoacán, México. 2 Instituto de Física-UNAM, Apartado Postal 20-364, 01000 México, D. F., México. ABSTRACT In this work, we report the production of MoSe 2 (molybdenum diselenide) nanotubes formed by irradiating the samples with high doses of electron irradiation. The irradiation was performed on a 2 MeV Van de Graaff accelerator at the following conditions: voltage 1.3 MeV, current 5µA current, dose rate 25 kGy/min, and total dosage 1 MGy. We observed well-defined nanotubes of several nm long and few nm wide, which suppose to be hollow and capped at one end. As the level of irradiation was increased to 1 MGy, elongated onion-like structures were observed. INTRODUCTION Carbon nanotubes were discovered by Iijima [1] in 1991, which prompted numerous studies because of their superior mechanical property [2] and unique electronic behavior [3]. For example nanotubes are expected to have a high strength-to-weight ratio [4] which is advantageous in advanced composites to be used in high performance materials such as aircraft frames. The small dimensions of the tubes shows promise for use as gas adsorption medium [5,6], a field emitter for use in flat-panel display [7], nanoscale electronic devices [8], and lately they have been used as microscope probes [9]. In 1992, Ugarte [10] reported that electron irradiation of carbon soot produced onion-like structures. Ugarte obtained such structures under a high flux of electrons in a transmission electron microscope (TEM). The graphite structure is also showed by metal dichalcogenides, represented by MX 2 ( M = Mo, W, Nb, etc., whilst X = S, Se, Te, etc.). In our case MoSe 2 , which its layered structure is depicted in Fig. 1. Still all the members of these family might present similar behavior and possible formation of nanotubes and onion-like structures, only MoS 2 and WS 2 compounds and few variation of them, have been extensively synthesized up to now. Lately, Galván et el. reported nanotube formation on MoTe 2 [11], WSe 2 [12] and NbSe 2 [13]. EXPERIMENTAL METHOD In this work we report the formation of nanotube structures in MoSe 2 (molybdenum selenide) also known as Drysdallite. The initial samples were obtained from commercial Mat. Res. Soc. Symp. Proc. Vol. 706 © 2002 Materials Research Society Z6.9.1