Date of Award
Doctor of Philosophy in Applied Physics - (Ph.D.)
Federated Physics Department
John Francis Federici
Robert Benedict Barat
Dale E. Gary
N. M. Ravindra
P. K. Swain
Significant scientific and technical challenges within the terahertz (THz) frequency regime have recently motivated an array of new research activities. This involves numerous applications of this region of the electromagnetic spectrum between approximately 100 GHz (3mm) and 3 THz (100 µm) for both spectroscopy and imaging purposes. THz time domain spectroscopy is unique in that the time domain waveforms are measured and the complex optical constants are deduced directly without resorting to the Kramers-Kronig Analysis.
In this work, THz spectroscopy has been used to characterize different types of materials. Materials investigated consisted of semiconductors, gate dielectric materials, high energetic materials and cyclic olefin polymers. Besides demonstrating that surface roughness affects the THz transmission, one of the most significant contributions of this work has been to deduce the number of defect states in buried layers. The study also attempts to develop a preliminary model based on effective medium approximations to predict the thickness of the interfacial layer which might be having a myriad of applications in the semiconductor industry. The characterization of a cyclic olefin polymer showed that it is probably the "candidate of the future" for fabrication of far infrared optics mainly because of its low loss and transparency in both the visible and far infrared region of the EM spectrum.
Sengupta, Amartya, "Novel characterization of materials using THz spectroscopic techniques" (2006). Dissertations. 777.