OptoElectronic Materials Laboratory

Location: JFB 326-333
Director: Matthew C. DeLong
Assistant: Wayne L. Wingert

Principal products

We are now supplying research quantities of conducting polymers to laboratories throughout the world. Polymers include P ANi, (polyaniline), in either the emeraldine base or emeraldine hydrochloride state, PPV (unsubstituted poly-paraphenylenevinylene), DOO-PPV (oxydodecyl methoxy- and di-oxyoctyl-PPV), and DDO-PPP (di-oxydodecyl poly(paraphenylene)). We also supply information on appropriate solvents and how to spin films from these materials. A more complete description is available.

We are also the world's premier source of high purity and custom doped alkali halide and cyanide single crystals. We have grown all of the alkali halides, from LiF to CsI, in purities from zone refined to doped with numerous impurities or isotopes for specific applications. The principal applications for these crystals, grown by the Bridgman or Czochralski technique, are for research, both by students and faculty within our department and at universities and corporations throughout the world. Cyanides are either purified from commercially available reagents (LiCN, NaCN, and KCN) or synthesized here (RbCN and CsCN). Starting materials can be purified by vacuum drying and/or sublimation, chemical gettering and zone refining.

In addition to single crystals, we also have expertise at synthesizing chalcogenide glasses such as (copper, silver)arsenic sulfide and selenide and germanium arsenic selenide. These can be either the pure alloys or doped with rare earths.

Cutting and Polishing of Semiconductors and Optical Materials

We have developed techniques for edge-polishing silicon wafers for depth profiling (e.g. via atomic force microscopy). We are able to produce surfaces with atomically abrupt edges which are atomically flat over areas of 1 (µm)². III-V substrates have been polished at a variety of angles up to 15 off those commercially available for subsequent epitaxy. Opal surfaces have been prepared for SEM.

Thin Film Deposition

We have facilities for deposition of metallic films on areas up to 15"/40 mm cross-section. Using this capability we have, for example, produced large quantities of parabolic aluminum front-surface mirrors on plastic for the CASA cosmic ray detector located at Dugway Proving Ground. Sputtering can be used to deposit silicon or chalcogenide glasses onto a variety of substrates.

Characterization and Analysis

The quantum efficiency of conducting polymers can be measured by standard integrating sphere photometric techniques with visible or UV excitation.

Our LEO 440i scanning electron microscope may be used either by our staff or trained users from other departments or local industry to image specimens down to 10 nm, perform qualitative or quantitative chemical analysis on the cubic micron scale with EDAX or pattern resists with our e-beam lithographic facility. Images may be stored on disk, on paper or photographically. Ancillary equipment, including sputtered gold and evaporated carbon and a resist spinner are also available.

In addition to synthesis and crystal growth, we have available a broad variety of characterization techniques, including Laue x-ray orientation of crystals in specific crystallographic directions. Metallic impurities and dopants are determined by atomic absorption/flame emission spectrophotometry; OH/OD and CN are determined by wet chemical technique

There are also extensive facilities for optical characterization, primarily of semiconductor materials. These techniques include a number of variations of photoluminescence(time resolved, temperature dependent, selectively excited and a unique spectroscopy called microwave modulated PL in which the materials are placed in a microwave cavity) as well as photoluminescence excitation (PLE), photothermal deflection spectroscopy, a technique for measuring very low absorption coefficients, and optically detected magnetic resonance (ODMR).Conventional transmission-absorption is measured from the UV to near-IR; the near- to-far-IR region of the spectrum is covered by Fourier transform spectroscopy (FTIR). Microwave modulated photoluminescence is an important tool for resolving recombination processes not resolved in conventional PL, for helping identify processes observed in PL and for estimating the relative importance of radiative and non-radiative recombination channels. The Hall effect can be measured from room temperature to 10 K.

Send inquiries to Matthew C. DeLong -- delong@physics.utah.edu
Phone: 801-581-7462, or Fax: 801-581-4801