PHYSICS/BK21 SEMINAR[09.09.30]
관련링크
본문
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Ultrabroadband Terahertz Spectroscopy
of Semiconductor Nanostructures
♦ Speaker : Dr. Hyunyong Choi [Lawrence Berkeley National Laboratory]
♦ Place : Physics Seminar Room (Science Bldg, 3-201)
♦ Date & Time : Sep, 30(Wed) 4:00 ~ 5:00 pm
Abstract
The terahertz (THz) electromagnetic wave - frequency range broadly defined as 0.1-30 THz (1 mm -15 ㎛ wavelength) - is at the interface of modern electronics and photonics. This electromagnetic spectrum has been much less explored and has been called theterahertz gapdue to the lack of efficient, room-temperature sources and detectors. Despite these difficulties, there has been recent explosion of interest in using THz pulse to address many questions in chemistry, physics, and material sciences.
Perhaps the most important aspect of contemporary electronics is to understand the charge conduction process. Typical electrical characterization of nanostructures (1 nm = 10⁻⁹ m) by attaching metal wires becomes an extremely challenging work to study those structures. One of many attractive features of the THz spectroscopy is it provides a non-contact electrical probe, thus circumvents many constraints of conventional measurement techniques.
In this talk, I will discuss how ultrashort THz pulse from femtosecond (1 fs = 10⁻¹⁵s) solid-state laser sources can be generated and detected, and further used to investigate dynamical or localized conduction processes in semiconductor nanostructures, e.g. graphene, carbon nanotube, semiconductor nanowire, and heterostructure solar cells. By measuring both amplitude and phase of the multi-THz waves, one can directly access the conductivity information of the nanostructures with sub-cycle temporal resolution.
"
Ultrabroadband Terahertz Spectroscopy
of Semiconductor Nanostructures
♦ Speaker : Dr. Hyunyong Choi [Lawrence Berkeley National Laboratory]
♦ Place : Physics Seminar Room (Science Bldg, 3-201)
♦ Date & Time : Sep, 30(Wed) 4:00 ~ 5:00 pm
Abstract
The terahertz (THz) electromagnetic wave - frequency range broadly defined as 0.1-30 THz (1 mm -15 ㎛ wavelength) - is at the interface of modern electronics and photonics. This electromagnetic spectrum has been much less explored and has been called theterahertz gapdue to the lack of efficient, room-temperature sources and detectors. Despite these difficulties, there has been recent explosion of interest in using THz pulse to address many questions in chemistry, physics, and material sciences.
Perhaps the most important aspect of contemporary electronics is to understand the charge conduction process. Typical electrical characterization of nanostructures (1 nm = 10⁻⁹ m) by attaching metal wires becomes an extremely challenging work to study those structures. One of many attractive features of the THz spectroscopy is it provides a non-contact electrical probe, thus circumvents many constraints of conventional measurement techniques.
In this talk, I will discuss how ultrashort THz pulse from femtosecond (1 fs = 10⁻¹⁵s) solid-state laser sources can be generated and detected, and further used to investigate dynamical or localized conduction processes in semiconductor nanostructures, e.g. graphene, carbon nanotube, semiconductor nanowire, and heterostructure solar cells. By measuring both amplitude and phase of the multi-THz waves, one can directly access the conductivity information of the nanostructures with sub-cycle temporal resolution.
"
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