Berlin 2015 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 95: Poster IV B (Quantum dots and wires: Prepration, characterization, optical properties, and transport)
HL 95.25: Poster
Donnerstag, 19. März 2015, 14:00–20:00, Poster B
Electrical properties of free-standing GaAs nanowires by multi-tip scanning probe microscopy — •Ilio Miccoli1,2, Frederik Edler1, Nico Lovergine2, Paola Prete3, Christoph Tegenkamp1, and Herbert Pfnür1 — 1Institut für Festkörperphysik, Leibniz Universität Hannover, DE — 2Dept. Innovation Engineering, Salento University, IT — 3IMM-CNR, Lecce, IT
Free-standing III-V nanowires (NWs) represent the forefront of materials science, and it is expected they will impact several technological fields, ranging from nanoelectronics to nano-photonics. Huge progress has been made in the vapour-liquid-solid growth by MOVPE technology of III-V NWs. However, further efforts are needed for the precise control of their electrical properties, especially in terms of dopant concentration and distribution profiles. Even more critical, the NW current-voltage (I-V) analysis usually requires the multi-step and time-consuming EBL/FIB-assisted fabrication of NW-based FET devices, which often alter the genuine NW transport properties. Recently, single-tip scanning tunnelling microscope (STM) has proven to be a versatile tool for the structural and electrical characterization of free-standing NWs, although the I-V characteristic is often dominated by the metal-catalyst/NW Schottky interface. Here, we show that the use of a multi-probe STM allows for the rapid sub-nanometric placement of three probe tips on free-standing n-/p-doped GaAs NWs. The NW transport properties are studied as function of NW diameter and along the NW lateral facet, and finally correlated with growth conditions.