Infrared detectors based on mercury-cadmium-telluride (MCT) are of much importance for sensing applications. However, the reliable growth of MCT material of high quality on large-area substrates is currently considered to be a major stumbling block. In this proposal, advanced electron microscopy methods will be used in close conjunction with growth studies being conducted by our collaborators. to achieve significant improvements in MCT detectors and devices. Techniques to be used for materials characterization will include high-resolution imaging. nano-probe spectroscopy. and convergent-beam electron diffraction. The characterization effort will be targeted towards two distinct topics. One focus will be on the reduction of growth defects in MCT films grown using the technique of molecular beam epitaxy (MBE). Materials deposited by MBE onto conventional CdZnTe. as well as alternative composite substrates based on silicon. will be systematically examined. so that the relative importance of lattice mismatch. valence mismatch. and thermal expansion in causing threading dislocations and other growth defects can be determined. The second area of activity will be characterization of MCT surface passivation. which can have a serious adverse effect on device characteristics such as dark current and noise levels. Measurements of device performance will be carried out in parallel with our microstructural studies to enable the surface treatment and annealing conditions to be optimized. The combined result of these collaborative studies should be improved materials and devices of much enhanced performance.
|Effective start/end date||10/1/09 → 3/31/13|
- DOD-ARMY-ARL: Army Research Office (ARO): $520,548.00
mercury cadmium tellurides
molecular beam epitaxy