Electron dephasing and decoherence of neutral donor bound electrons in GaAs
Strong oscillator strengths, small inhomogeneous broadenings of the optical transitions, and semi... more Strong oscillator strengths, small inhomogeneous broadenings of the optical transitions, and semiconductor device integration possibilities make the GaAs donor-bound exciton (D0X) system an attractive candidate for electromagnetically induced transparency based applications. However, the recent observation of coherent population trapping in the GaAs D0X system indicates a fast (1-2 ns) dephasing rate of the bound- electron spin states which severely limits
<title>Compact standing-wave Fourier-transform interferometer with harmonic spectral analysis</title>
Coherence Domain Optical Methods and Optical Coherence Tomography in Biomedicine X, 2006
A new technique utilizing harmonic Fourier spectra created by the non-linear properties of a comp... more A new technique utilizing harmonic Fourier spectra created by the non-linear properties of a compact Fourier transform infrared interferometer (FTIR) was proposed and realized to improve the system resolution. The compact standing wave FTIR (SWFTIR) system consists of a partial transparent hetero-junction bipolar phototransistor (HPT) and a free scanning highly reflective mirror. The overall size of the system is less
<title>Crystalline state of InSb epilayers on GaAs substrates by metalorganic chemical vapor deposition</title>
Third International Conference on Thin Film Physics and Applications, 1998
Plastic flows of a large lattice-mismatch InSb epilayer on GaAs substrate grown by metalorganic c... more Plastic flows of a large lattice-mismatch InSb epilayer on GaAs substrate grown by metalorganic chemical vapor deposition (MOCVD) were first observed by scanning electron acoustic microscopy (SEAM), and crystalline state of the buried subsurfaces was discussed. From the SEAM images in two different positions a macroscopical heterogenous distribution of large compression stress fields was studied. It was a very important
The origins of image contrast in SEAM of ferroelectric semiconductor, ceramics and single crystal: BaTiO/sub 3/
9th International Symposium on Electrets (ISE 9) Proceedings, 1996
A relatively new imaging technique, scanning electron-acoustic microscope (SEAM), was used to inv... more A relatively new imaging technique, scanning electron-acoustic microscope (SEAM), was used to investigate the ferroelectric semiconductors, ferroelectric ceramics and single crystal: BaTiO3 . The subsurface defects of ferroelectric semiconductors and the domain structures of ferroelectric ceramics and single crystal were observed without any pre-handling to the samples in the electron-acoustic imaging of these materials. The origins of image contrast in
Acquisition of modulated PZT signal and application of SEAM
9th International Symposium on Electrets (ISE 9) Proceedings, 1996
PZT transducers can be used to measure the characteristics of materials irradiated by laser or el... more PZT transducers can be used to measure the characteristics of materials irradiated by laser or electron beams. In order to maintain high measurement resolution, the signal aroused on the transducer is modulated to produce a modulated PZT signal. Signal acquisition is accomplished with a lock-in amplifier and computer technologies. A typical application is SEAM (Scanning Electrical Acoustic Microscopy). The SEAM image reflects the thermal characteristics of materials. Furthermore, the SEAM image can supply subsurface information without destroying the sample
Theoretical ratio of hot electron current to thermal electron current in scanning hot electron microscopy
Journal of Applied Physics, 2001
Theoretical calculation of the ratio of hot electron current to thermal electron current in scann... more Theoretical calculation of the ratio of hot electron current to thermal electron current in scanning hot electron microscopy (SHEM) is reported by modeling the sample-tip structure as a plane-sphere structure. The effects of hot electron energy, gap separation, and applied bias between the tip and the sample surface on the ratio are investigated. Comparison of the results of theoretical calculation
Theoretical Relation between Spatial Resolution and Efficiency of Detection in Scanning Hot Electron Microscope
Japanese Journal of Applied Physics, 2000
To observe the spatial distribution of subsurface hot electrons (HEs) with a scanning probe, the ... more To observe the spatial distribution of subsurface hot electrons (HEs) with a scanning probe, the relation between the spatial resolution and the hot electron current is investigated theoretically and the efficiency of HE detection is discussed. Using a sphere-plane model for the tip and the sample surface in a scanning hot electron microscope (SHEM), the electrostatic potential and the tunnel
Design and Experimental Characteristics of n-Si/CaF 2 /Au Hot Electron Emitter for Use in Scanning Hot Electron Microscopy
Japanese Journal of Applied Physics, 1999
For scanning hot electron microscopy experiments, n-Si/CaF2/Au hot electron emitters were designe... more For scanning hot electron microscopy experiments, n-Si/CaF2/Au hot electron emitters were designed and fabricated to characterize the emission properties. A self-consistent method was used in analyzing the hot electron energy and the tunneling current density while considering the quantum mechanical effects in the space-charge region. By comparison of the theoretical calculations with the experimental results for current density, the tunneling
Some New Applications of the Scanning Electron Acoustic Microscope for Materials Evaluation
Japanese Journal of Applied Physics, 1998
Several different kinds of materials were investigated by an improved scanning electron acoustic ... more Several different kinds of materials were investigated by an improved scanning electron acoustic microscope (SEAM). Residual stress distribution in aluminum metal and whisker-reinforced АЬОз-SiCw ceramic induced by Vicker's indentation, domain structures in a ...
A compact standing-wave Fourier transform interferometer is experimentally demonstrated in a very... more A compact standing-wave Fourier transform interferometer is experimentally demonstrated in a very broad band. By using an InP-InGaAs-InAlAs heterojunction bipolar phototransistor (HPT) and a PZT-controlled scan mirror, a resolution of 37.5 cm 1 was achieved with a mirror travel length of only 32 m at the fifth harmonic order spectrum component. The experimental results agree well with the mathematical models, and the interferometer resolution could be further improved.
Computer-controlled image acquisition and processed system for scanning electron -acoustic microscopy
Ferroelectrics, 1997
Scanning Electron Acoustic Microscopy(SEAM) with the piezoelectric ceramic sensor is a novel inst... more Scanning Electron Acoustic Microscopy(SEAM) with the piezoelectric ceramic sensor is a novel instrument in materials analysis. Normally the signal detected by the sensor is very weak. Signal to noise ratio should be enhanced in order to observe electron acoustic image with good quality. In this paper, the time averaging data acquisition system with computer was described and the data transferred into imaging were processed with a computer. Electron acoustic pictures on PZT-type materials were shown in real time and refined and memorized in computer. Results can also be recalled on the screen at any time.
Application of scanning electron acoustic microscope to ferroelectric semiconductor material:BaTiO 3 +Y 2 O 3
Ferroelectrics, 1997
In this paper, Scanning Electron Acoustic Microscope (SEAM) is used to investigate ferroelectric ... more In this paper, Scanning Electron Acoustic Microscope (SEAM) is used to investigate ferroelectric semiconductor ceramics BaO3+Y2O3. The linear electron acoustic amplitude images about the nature surface features of this material were successfully obtained at different modulated frequencies. Electron acoustic signal generation and image contrast mechanisms are discussed. By means of analyzing surface and subsurface structure, ferroelectric and semiconductor properties of ferroelectric semiconductor materials from electron acoustic images we try to build a new way to characterize ferroelectric semiconductor materials on a micro-scale.
Monolithic integration of quantum dot containing microdisk microcavities coupled to air-suspended waveguides
Applied Physics Letters, 2009
ABSTRACT GaAs microdisk microcavities coupled to monolithic air-suspended waveguide structures ar... more ABSTRACT GaAs microdisk microcavities coupled to monolithic air-suspended waveguide structures are fabricated with out-of-plane light coupling achieved via the grating couplers monolithically integrated in the input and output ports. Photoluminescence signal of the whispering gallery modes is extracted from the grating couplers through the waveguide. Quality factors of modes are obtained through a transmission measurement with quality factors of up to 9500 and transmission depth of ΔT = 35%.
Electron dephasing and decoherence of neutral donor bound electrons in GaAs
Strong oscillator strengths, small inhomogeneous broadenings of the optical transitions, and semi... more Strong oscillator strengths, small inhomogeneous broadenings of the optical transitions, and semiconductor device integration possibilities make the GaAs donor-bound exciton (D0X) system an attractive candidate for electromagnetically induced transparency based applications. However, the recent observation of coherent population trapping in the GaAs D0X system indicates a fast (1-2 ns) dephasing rate of the bound- electron spin states which severely limits the achievable transparency. Theoretical and experimental research in other groups indicate the fast dephasing is due to the random nuclear spin environment in the GaAs lattice. We perform measurements of the electron Zeeman Raman transition linewidth which confirm the 1-2 ns dephasing rate. Using this technique, we study the effect of doping density and magnetic field on the Raman linewidth. Both variables can theoretically affect the inhomogeneous broadening due to the nuclear spin environment. If the inhomogeneous broadening can be decreased, spin-echo techniques should be possible to further increase the spin dephasing time to the homogeneous microsecond regime.
Advanced Optical Concepts in Quantum Computing, Memory, and Communication (Proceedings Volume)
... Author(s): Eugene Ya. Glushko. Toward measurement-based quantum computing using solid state s... more ... Author(s): Eugene Ya. Glushko. Toward measurement-based quantum computing using solid state spins. Author(s): Jason M. Smith; Brian Patton; Fabio Grazioso. Quantum spin memories and dot lattice polaritons in planar microcavities. ...
A technique to electrically pump photonic crystal nanocavities using a lateral p-in junction is d... more A technique to electrically pump photonic crystal nanocavities using a lateral p-in junction is described. Ion implantation doping is used to form the junction, which under forward bias pumps a gallium arsenide photonic crystal nanocavity with indium arsenide quantum dots. Efficient cavity-coupled electroluminescence is demonstrated and the electrical characteristics of the diode are presented. The fabrication improvements necessary for making an electrically pumped nanocavity laser using a lateral junction are discussed.
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