Areas of Research:

Professor Mohney’s research group investigates electronic and photonic materials. Many of our projects focus on metal/semiconductor contacts for electronic and optoelectronic devices. We are also investigating semiconductor nanowires for nanoscale electronics and quantum dots for more efficient white lighting. In addition, we study metallic thin films for interconnects, electronic packaging, and microelectromechanical systems (MEMS).

The metal/semiconductor contacts we study are an essential part of electronic and optoelectronic devices, including transistors, laser diodes, and solar cells. Controlled metallurgical reactions between the contact metals and the semiconductor are required to engineer the electrical properties of the contacts. On the other hand, uncontrolled reactions can result in nonuniform contacts and poor thermal stability during processing, packaging, or long-term operation. Through an examination of the thermodynamics and kinetics governing interfacial reactions, contacts with greatly improved thermal stability, uniformity, and electrical performance can be designed. This work also involves study of current transport in the contacts and materials characterization using techniques such as transmission electron microscopy, Auger depth profiling, and atomic force microscopy. We work with many families of semiconductors, some of which have been commercialized and others that are in the early stages of development. These materials include III-V compound semiconductors, GaN, SiC, Si, and icosahedral borides.

Our research on semiconductor nanowires and quantum dots, MEMS, and novel semiconductors is very interdisciplinary, involving collaborations with faculty in electrical engineering, physics, chemical engineering, and other materials disciplines. We also frequently work with researchers from government laboratories and industry.

Journal Articles and Publications:
1. S. E. Mohney, Y. Wang, M. A. Cabassi, K. K. Lew, S. Dey, J. M. Redwing, and T. S. Mayer. 2005. Measuring the specific contact resistance of contacts to semiconductor nanowires. Solid-State Electronics 49(2):227–232.

2. M. A. Miller and S. E. Mohney. V/Al/V/Ag ohmic contacts to n-AlGaN/GaN heterostructures with a thin GaN cap. 2007. Applied Physics Letters 91(1):012103.

3. Z. N. Tan, F. Zhang, T. Zhu, J. Xu, A. Y. Wang, D. Dixon, L. S. Li, Q. Zhang, S. E. Mohney, and J. Ruzyllo. 2007. Bright and color-saturated emission from blue light-emitting diodes based on solution-processed colloidal nanocrystal quantum dots. Nano Letters 7(12):3803-3807.

4. B. Z. Liu, Y. F. Wang, T. T. Ho, K. K. Lew, S. M. Eichfeld, J. M. Redwing, T. S. Mayer, and S. E. Mohney. 2008. Oxidation of silicon nanowires for top-gated field effect transistors. Journal of Vacuum Science and Technology A 26(3):370-374.

5. E. M. Lysczek and S. E. Mohney. Selective deposition of ohmic contacts to p-InGaAs by electroless plating. 2008. Journal of The Electrochemical Society 155(10):H699-H702.