Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 15: Quantum Dots and Wires: Fabrication and Devices

HL 15.12: Vortrag

Montag, 7. März 2016, 18:15–18:30, H16

Electrical characterization and modelling of p-GaAs nanowires by MT-STM — •Andreas Nägelein¹, Matthias Steidl¹, Weihong Zhao¹, Stefan Korte², Peter Kleinschmidt¹, and Thomas Hannappel¹ — ¹TU Ilmenau, Institut für Physik, FG Photovoltaik, 98693 Ilmenau — ²Forschungszentrum Jülich, Peter Grünberg Institut (PGI-3), 52425 Jülich

Doped nanowires are promising candidates as components for advanced applications such as FETs or solar cells. To increase the efficiency of these upcoming applications detailed knowledge of dopant distribution along the nanowire is necessary. In this work a nondestructive method is used, where freestanding nanowires can be characterized using a multi-tip STM (MT-STM) as a prober for four-point measurements. Here, a continuous resistance profile can be recorded which is proportional to the doping profile. The nanowires were grown in the Au-catalyzed VLS growth mode on p-GaAs(111)B by metal-organic chemical vapor phase epitaxy (MOVPE) in an “AIX200” system.
Resistance profiles of p-GaAs nanowires were recorded using the MT-STM. With help of a suitable model we are able to simulate the resistances and calculate the doping of the nanowire which results in a constant doping profile. In order to establish a valid electrical model for doped nanowires we developed in the first step a simulation with resistances and diodes. We could show that a simple model is in good agreement with the measured data. Applying an extended model to nanowire measurements allows analysis of more complex dopant distributions and nanowire geometries.