This paper describes a real-time transmission-type Terahertz (THz) microscope, with palm-size THz camera and compact quantum cascade laser (QCL). The THz camera contains 320x240 microbolometer focal plane array which operates at 30 Hz frame rate and has lock-in imaging function as well as integration functions such as frame integration and spatial filter. These functions are found very powerful in improving signal-to-noise ratio. QCL is installed in compact Stirling cycle cooler. A variety of QCLs covers frequency range from 1.5 to 5 THz and provides time-average power of 0.5~2 mW. The illumination area for sample is changed by adjusting one lens in the illumination optics. Performances of the THz microscope, such as signal-to-noise ratio and so on, were measured and are found consistent with the calculations. THz images taken with the THz microscope are finally presented.
Spectacular breakthroughs have been achieved in optoelectronics with the use of ZnO as a source for light-emitting
diodes (LED) and quantum wells (QWs). In particular, atomically flat surfaces were obtained in Zn-polar growth, which
led to the fabrication of Mg-rich Mg0.37Zn0.67O/ZnO QWs with sharp heterointerfaces between MgZnO and ZnO. μ-PL
spectroscopy revealed that excitons were efficiently confined in the wells at room temperature. Excitonic emissions from
Zn-polar QWs did not have a linear polarization effect, although polarized lights were clearly observed in M-nonpolar
Mg0.12Zn0.88O/ZnO QWs. From the optical selection rule, the polarized lights of excitonic emissions were based on A- and
C-excitonic transitions under E⊥c and E//c configurations. Furthermore, the anisotropic surface morphology was
self-organized on the M-nonpolar ZnO layer surfaces, which allowed examination of the relationship between electron
transport and surface morphology. The observed transport anisotropy correlated with the surface morphology. On the
other hand, Zn-polar QWs resulted in isotropic electron transport because of two-dimensional surfaces. In this
presentation, we introduce the detailed growth and various properties of Zn-polar and M-nonpolar QWs.
The development of epitaxial growth techniques for the fabrication of nanostructures provides advantages for
nanoscale engineering and has yielded many impressive results. ZnO possesses attractive characteristics that include
optical, electric and magnetic properties. This material can be utilized to delineate new phenomena through an
investigation of surface nanostructures and quantum heterostructures. Homoepitaxy in ZnO can generate specific growth
directions in the absence of lattice mismatch at the interface between the film and substrate. Many reports have appeared
in the past year concerning the layer growth of nonpolar ZnO. Nonpolar planes are expected to yield large in-plane
anisotropy in electrical and optical characterizatics. In nonpolar (10-10) growth using laser-MBE, we found that novel in
situ growth techniques allowed for the fabrication of dense arrays of conductive one-dimensional nanostripes with a high
degree of lateral periodicity. Highly anisotropic surface morphologies markedly influenced electron transport of ZnO
single layers and Mg0.12Zn0.88O/ZnO multi-quantum wells (MQWs) with conductivity parallel to the nanostripe arrays being more than one order of magnitude larger than that observed perpendicular to the nanostripe arrays.
Conference Committee Involvement (4)
Micro- and Nanotechnology: Materials, Processes, Packaging, and Systems IV
10 December 2008 | Melbourne, Australia
Micro- and Nanotechnology: Materials, Processes, Packaging, and Systems III
11 December 2006 | Adelaide, Australia
Device and Process Technologies for Microelectronics, MEMS, and Photonics IV
12 December 2005 | Brisbane, Australia
Micro- and Nanotechnology: Materials, Processes, Packaging, and Systems II
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.