49 research outputs found
Effects of Poultry Manure Application on Phosphorus in Soil and Tile Drain Water Under a Corn-Soybean Rotation
Photoluminescence enhancement of the single InAs quantum dots through plasmonic Au island films
Single-photon property characterization of 1.3 mu m emissions from InAs/GaAs quantum dots using silicon avalanche photodiodes
Electron spin relaxation in a single InAs quantum dot measured by tunable nuclear spins
The electron-spin dynamics of positively charged excitons in a single InAs quantum dot (QD) were measured by time-resolved photoluminescence spectroscopy. Using alternating sigma(+)/sigma(-) pulse sequences to excite the QD, the lattice nuclear spins remained randomly oriented. This method enables us to check the theory of electron-spin relaxation in the randomly distributed frozen fluctuation of the nuclear field. The experimental results are in qualitative agreement with theoretical prediction, showing that the electron-spin polarization decreases to a minimum value at first, and then increases again up to a steady value of about 1/3 of its initial value
Fine structural splitting and exciton spin relaxation in single InAs quantum dots
We have studied the exciton spin dynamics in single InAs quantum dots (QDs) with different exciton fine structural splitting (FSS) by transient luminescence measurements. We have established the correlation between exciton spin relaxation rate and the energy splitting of the FSS when FSS is nonzero and found that the spin relaxation rate in QD increases with a slope of 8.8x10(-4) ns(-1) mu eV(-1). Theoretical analyses based on the phonon-assisted relaxations via the deformation potential give a reasonable interpretation of the experimental results
Single-photon emission from a single InAs quantum dot
Excitation power-dependent micro-photoluminescence spectra and photon-correlation measurement are used to study the optical properties and photon statistics of single InAs quantum dots. Exciton and biexciton emissions, whose photoluminescence intensities have linear and quadratic excitation power dependences, respectively, are identified. Under pulsed laser excitation, the zero time delay peak of second order correlation function corresponding to exciton emission is well suppressed, which is a clear evidence of single photon emission
Temperature dependence of photoluminescence from single and ensemble InAs/GaAs quantum dots
We investigate the temperature dependence of photoluminescence from single and ensemble InAs/GaAs quantum dots systematically. As temperature increases, the exciton emission peak for single quantum dot shows broadening and redshift. For ensemble quantum dots, however, the exciton emission peak shows narrowing and fast redshift. We use a simple steady-state rate equation model to simulate the experimental data of photoluminescence spectra. It is confirmed that carrier-phonon scattering gives the broadening of the exciton emission peak in single quantum dots while the effects of carrier thermal escape and retrapping play an important role in the narrowing and fast redshift of the exciton emission peak in ensemble quantum dots
Single-photon emission at liquid nitrogen temperature from a single InAs/GaAs quantum dot
We report on the single photon emission from single InAs/GaAs self-assembled Stranski-Krastanow quantum dots up to 80K under pulsed and continuous wave excitations. At temperature 80 K, the second-order correlation function at zero time delay, g((2))(0), is measured to be 0.422 for pulsed excitation. At the same temperature under continuous wave excitation, the photon antibunching effect is observed. Thus, our experimental results demonstrate a promising potential application of self-assembled InAs/GaAs quantum dots in single photon emission at liquid nitrogen temperature