title: THz acoustic phonon spectroscopy and nanoscopy by using piezoelectric semiconductor heterostructures.
abstract: Thanks to ultrafast acoustics, a better understanding of acoustic dynamics on a short time scale has been obtained and new characterization methods at the nanoscale have been developed. Among the materials that were studied during the development of ultrafast acoustics, nitride based heterostructures play a particular role due to their piezoelectric properties and the possibility to generate phonons with over-THz frequency and bandwidth. Here, we review some of the work performed using this type of structure, with a focus on THz phonon spectroscopy and nanoscopy. First, we present a brief description of the theory of coherent acoustic phonon generation by piezoelectric heterostructure. Then the first experimental observation of coherent acoustic phonon generated by the absorption of ultrashort light pulses in piezoelectric heterostructures is presented. From this starting point, we then present some methods developed to realize customizable phonon generation. Finally we review some more recent applications of these structures, including imaging with a nanometer resolution, broadband attenuation measurements with a frequency up to 1THz and phononic bandgap characterization.
authors.affiliation: Department of Electrical Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Pierre-Adrien
authors.initials: PA
authors.lastname: Mante
authors.affiliation: Department of Electrical Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Yu-Ru
authors.initials: YR
authors.lastname: Huang
authors.affiliation: Department of Electrical Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Szu-Chi
authors.initials: SC
authors.lastname: Yang
authors.affiliation: Institute of Biomedical Engineering, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Tzu-Ming
authors.initials: TM
authors.lastname: Liu
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Alexei A
authors.initials: AA
authors.lastname: Maznev
authors.affiliation: Institute of Electro-Optical Science and Engineering and Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 70101, Taiwan.
authors.forename: Jinn-Kong
authors.initials: JK
authors.lastname: Sheu
authors.affiliation: Department of Electrical Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan; Molecular Imaging Center, National Taiwan University, Taipei 10617, Taiwan; Institute of Physics and Research Center for Applied Sciences, Academia Sinica, Taipei 115, Taiwan. Electronic address: sun@ntu.edu.tw.
authors.forename: Chi-Kuang
authors.initials: CK
authors.lastname: Sun
mesh_terms: D036103:Nanotechnology; D060739:Phonons; D012666:Semiconductors; D013057:Spectrum Analysis / Q000379:methods*