Date of Award
2023
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Optical Science and Engineering
Committee Chair
Lingze Duan
Committee Member
Don Gregory
Committee Member
Seyed Sadeghi
Committee Member
Patrick Reardon
Committee Member
Hemang Jani
Subject(s)
Gallium arsenide, Photocathodes, Ultrashort laser pulses, Nanotechnology
Abstract
Gallium Arsenide (GaAs) is one of the most important semiconductors in the field of photonics and has been the focus of extensive studies since the 1960s. In particular, GaAs photonic devices such as GaAs diode lasers and GaAs photocathodes have attracted tremendous interest owing to their superb features and wide ranges of applications. Despite the success of past research, the advancement of new theoretical models and experimental techniques continues to offer new insights into the properties of GaAs and the potentials of GaAs photonic devices. The work presented in this dissertation represents our most recent effort towards understanding the ultrafast photoelectron dynamics in GaAs wafers and GaAs photocathodes. Theoretically, analytical and numerical models are established to describe photoelectron transportation in GaAs photocathodes with different doping structures following the photoexcitation of femtosecond laser pulses. Experimentally, the time-resolved transient reflectivity of actual devices is measured with the few-cycle pump-probe reflectometry. The excellent agreement found in the theory-experiment comparisons validates the effectiveness of the theoretical models and helps determine some key parameters of the tested samples. Furthermore, time- and wavelength-resolved spectrograms of GaAs wafers with different doping methods are obtained and analyzed. The observed carrier-induced band gap shifts indicate that the transient dispersion measurements are capable of revealing some hidden details of GaAs material and may be considered a potential tool for future semiconductor property studies.
Recommended Citation
Zhou, Rui, "Ultrafast photoelectron transportation in GaAs and GaAs-based devices" (2023). Dissertations. 285.
https://louis.uah.edu/uah-dissertations/285