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Materials Science and Engineering, University of Michigan

  MSE / People / Faculty / Rachel S. Goldman

Molecular Beam Epitaxy -- Varian GEN II

Location: 2058 H.H Dow

Our Reactive Molecular Beam Epitaxial (RMBE) Growth System consists of a 3" Modular Varian Gen II system. The RMBE contains facilities for in-situ Reflection High Energy Electron Diffraction (with a 30 keV Staibe RHEED system), in-situ optical pyrometry, and in-situ reflection mass spectroscopy (with a Stanford Research Systems 300 amu system). In addition, Ga, In, Al, Si, and Be solid sources plus a reactive nitrogen source enable growth of both n- and p-doped mixed anion nitride-arsenide materials. The RMBE system will soon be outfitted with a k-Space Associates multi-beam optical sensor (MOS). In addition, our Omicron Associates ultrahigh vacuum large-sample scanning tunneling microscope (LS-STM) is in the process of being attached to the RMBE (the LS-STM is shown in the right side of the picture above). The LS-STM head holds a 3" molybdenum block, and the tip may be positioned over a range of 10 x 10 square millimeters, with a continuously variable step size of 20-200 nm. The maximum xy scan size is 12 x 12 square micrometers and z range is 1.5 micrometers. Samples from the RMBE are transferred to the LS-STM chamber without breaking vacuum.

Cross-sectional Scanning Tunneling Microscopy

Location: 1176 G.G.Brown

Our ultra-high vacuum cross-sectional scanning tunneling microscopy system contains a Park Scientific Instruments VP II scanning probe microscope, configured for cross-sectional studies. The SPM functions as a scanning tunneling microscope and as an atomic force microscope (AFM). The AFM uses piezoresistive cantilevers (strain gauges) which are mounted to the same tip holders as the STM probe tips. Thus, it is possible to change from STM to AFM capabilities (and vice versa) simply by switching probe tip holders, without breaking vacuum. As both an STM and AFM, the instrument is capable of high resolution as well as wide-range scanning and positioning, as required for simultaneous atomic-scale and large-area cross-sectional studies of mixed anion nanostructures. This STM is also equipped for conductance (dl/dV) imaging STM spectroscopy, in order to measure lateral variations in effective band gaps across nanostructure interfaces. The system allows for in-situ sample cleaving and in-situ probe tip cleaning by electron bombardment. In addition, the system is capable of interchanging probe tips and samples through a load lock.

Electrical Characterization Facilities

Location: 2125 HH Dow

Our electrical characterization facilities include two Hall and Resistivity set-ups, one of which is a fixed-field (B=0.1 Tesla) set-up with a wide range of temperature capabilities (10K to 200C) and a second which has a temperature range (70 to 300K), with a variable field ranging from 0 to 3.5 kG. In addition, two Edwards thermal evaporation systems, for n- and p-type contact deposition, a Hewlett-Packard Semiconductor Parameter Analyzer, a Kulike and Soffa Wire Bonder, and a Bio-Rad contact annealing station are available.

Electron Microbeam Analysis Laboratory (EMAL)

Location: Basement in Space Research Building

The Electron Microbeam Analysis Laboratory (EMAL) is a user-facility that provides a broad spectrum of analytical and nano-mechanical testing equipment. Of particular interest for this program are the electron microscopes. These include a high-resolution transmission electron microscope (JEOL JEM-3011UHR), with a 0.14 nm lattice and 0.175 nm point-to-point resolution, and an analytical electron microscope (JEOL 2010F), with 0.1 nm lattice and 0.25 nm point-to-point resolution. The JEOL 2010F is also equipped with x-ray dispersive spectroscopy and parallel electron energy-loss spectroscopy. Also, an ambient atomic force microscope (Digital Instruments Nanoscope III), capable of contact and tapping mode AFM, STM, MFM, is availiable in EMAL. See website for more details: http://emalwww.engin.umich.edu/

Ion Beam Laboratory

Location: 120 NAME

The Ion Beam Laboratory has facilities for Rutherford backscattering spectrometry, ion channeling, nuclear reaction analysis, elastic recoil detection, and ion implantation over a large energy range (1 ke V to 5 Me V). See website for more details: http://www.engin.umich.edu/dept/nuclear/research/Mibl/index.html

Molecular Beam Epitaxy -- Riber

Location: 1176 GG Brown
The Riber model 32 MBE system is being configured for GaAsN growth to sipport the development of nanocrystal directed matrix seeding. It has two intro chambers and individual pumped sources for Ga, In, As, Be, and Si on the growth chamber. We are in the process of obtaining a RHEED system and N plasma source.
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