Berlin 2008 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 23: Quantum dots and wires: Transport properties I

HL 23.1: Talk

Tuesday, February 26, 2008, 11:00–11:15, EW 201

Determining doping concentration and mobility in GaN nanowires by opto-electrical characterization — •Thomas Richter, Michel Marso, Ralph Meijers, Raffaella Calarco, Detlev Grützmacher und Hans Lüth — Instiute of Bio- and Nanosystems (IBN1) and Centre of Nanoelectronic Systems for Information Tech-nology, Research Center Jülich, D-52425 Jülich, Germany

Nanostructures such as semiconductor nanowires have an increasing interest as possible candidates for novel beyond-CMOS nanodevice concepts. This is strongly motivated by their already proven high versatility and practical applications. Nevertheless of these promising achievements, there are still great challenges concerning fundamental questions of physics in those nanoscaling devices. Properties like the doping and resulting electrical transport are an important field of research. We report the growth of GaN nanowires by plasma-assisted molecular beam epitaxy on Si (111) substrate. These nanowires vary in density and diameter from 20 to 300 nm. For the electrical characterisation the nanowires GaN have then been transferred to a Si (100) substrate covered with a layer of SiO2. Single nanowire devices have been fabricated by e-beam patterning technique. The electrical transport properties of the resulting metal-semiconductor-metal nanostructures are analyzed by means of current voltage measurements. The transport in nanowires is extremely sensitive to the wire diameter due to the size dependent recombination barrier. This effect is used to determine doping level and mobility of the nanowires and to confirm our previously developed surface recombination model for GaN nanowires.