Nanofabrication

1. - Molecular Beam Epitaxy (MBE) Nanofabrication MnAs + - + ? GaAs Figure 2. Road to success. ? Electrical Spin Transport Measurements Fabrication and Characterization of MnAs/GaAs Heterostructures for Studies of One-Dimensional Spin Transport • MnAs is an attractive material for use in studies of ferromagnet/semiconductor heterostructures. It is a room-temperature ferromagnet and can be grown by Molecular Beam Epitaxy (MBE) on III-V semiconductors. In this work we present results detailing the fabrication and characterization of GaAs freestanding nanowires with MnAs caps. MnAs/GaAs freestanding nanowires with aspect ratios as great as 7:1 and diameters as small as 100nm have been fabricated using a Reactive Ion Etch (RIE) process. The structural properties of the nanowires were characterized using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Ongoing measurements of the magnetic and electrical properties of the nanowires are being conducted using Magnetic Force Microscopy (MFM) and Conductive Atomic Force Microscopy (CAFM). The fabrication and characterization of these MnAs/GaAs nanowires represent the first steps toward creating a ferromagnet/semiconductor heterostructure suitable for use in studies of one-dimensional electron spin transport. Figure 1. Device Design D. Toyli (U. of Minnesota) and D. Awschalom (UCSB) Work performed at UCSB NNIN_Nuggets.ppt