Compound Semiconductor Materials and Devices
(CSL & SSL)

Studies of III-V compound semiconductors and their device applications are the major research activities of Professors Lau and Anderson and their students. Heterostructures of binary and ternary compounds with strain and quantum size effects, as well as highfrequency, high-speed, and photonic devices based on these materials, are being investigated in the Compound Semiconductor Laboratory (CSL) and Semiconductor Spectroscopy Laboratory (SSL). Recent experimental and theoretical research projects involve novel THz sources and detectors, heterostructure field effect transistors, optical modulators and detectors, and semiconductor lasers. Fundamental studies of epitaxial growth by organometallic chemical vapor deposition, quantum-well electronic structure and optical properties, and new spectroscopic techniques are also being conducted by CSL and SSL researchers. Support of this research is provided primarily by grants from NSF, NASA, and Morton International.

Compound Semiconductor Laboratory Facilities (CSL). Facilities of the CSL are located in Rooms 4, 9, and 15B of Marcus Hall. A major facility in this lab is the computer-controlled OMCVD system, which is utilized for growth of a large variety of III-V quantum well and other heterostructures. A computerized Hall effect measurement system, a commercial C-V profiler with a mercury probe, and a home-built magnetoresistance and transconductance system are used for determining carrier concentrations, mobility and doping profiles. Low temperature electrical and magneto-photoluminescence measurements are made in a liquid helium dewar with a built-in superconducting magnet. A double crystal x-ray diffractometer is used for the measurement of alloy compositions and crystalline quality of the materials. Major facilities for device fabrication include a submicron mask aligner, a multi-target sputtering system, an E-beam evaporator, a plasma reactive ion etcher, and a scanning electron microscope. A submillimeter wave molecular laser and a pulsed CO2 laser are also available for device and material characterization.

Semiconductor Spectroscopy Laboratory (SSL) Facility. The SSL, located in Room 9-D of Marcus Hall, is devoted primarily to the optical characterization of advanced semiconductor materials and devices. Characterization techniques available in the SSL include photoluminescence, photoluminescence excitation, photoreflectance, electroreflectance, and photocurrent spectroscopies, as well as a new polarized excitation luminescence technique developed in the SSL which allows for improved identification of optical transition types. Facilities include an Argon-pumped tunable Ti:Sapphire laser system, broadband light sources, a 0.64m spectrometer system, liquid helium cryogenics for sample cooling to less than 4K, and a variety of detection and polarization devices. Considerable research effort in the SSL group is also devoted to theoretical aspects of CSL/SSL material and device studies.

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