Doping is essential for the realization of optoelectronic devices and represents a complex task if related to nanowires. We have studied GaN and InN nanowires (NWs) doped by Si and Mg obtained by catalyst-free MBE on Si(111) in N-rich conditions. Increasing the Si amount the morphology as well as the density of the wires changes. Successful n-doping of GaN nanowires has been shown by electrical and optoelectrical measurements. Due to the sensitivity of the electrical transport to the wire diameter (size dependent surface barrier), it was possible to determine the doping level of single nanowire. A small amount of Mg increases the tendency of the wires to coalesce. For InN nanowires doped with Si a reduced NWs density is observed as compared to the undoped counterpart. The Mg doping does not change the morphology of the NWs as compared to the undoped however some staking faults at the tip could be observed.
Stoica, Toma; Meijers, Ralph; Debnath, Ratan; Richter, Thomas; Lueth, Hans; Calarco, Raffaella;  Sutter, Eli;  Jeganathan, Kulandaivel;  Department of Physics, Bharathidasan University, Trichirappalli (India)]; Marso, Michel;  University of Luxembourg (Luxembourg). Faculty of Sciences, Technology and Communication]
- Institute of Semiconductor Nanoelectronics (IBN-1), Research Centre Juelich GmbH, D-52425 Juelich, JARA- Fundamentals of Future Information Technology (Germany)
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York (United States)