Phase-locked ring-defect photonic crystal vertical-cavity surface-emitting laser

Phase-locked oxide-confined ring-defect photonic crystal vertical-cavity surface-emitting laser is presented. The coupled-mode theory is employed to illustrate the two supermodes of the device, in-phase and out-of-phase supermode. Experimental results verify the two supermodes by the characteristics of the spectra and the far field patterns. At the lower current, only the out-of-phase supermode is excited, whereas under the higher current, the in-phase supermode also appears at the shorter wavelength range. In addition, the measured spectral separation between the two supermodes agrees well with the theoretical result.

CHARACTERIZATION OF HIGH FLUENCE NEUTRON-INDUCED DEFECT LEVELS IN HIGH-RESISTIVITY SILICON DETECTORS USING A LASER DEEP-LEVEL TRANSIENT SPECTROSCOPY (L-DLTS)

Neutron irradiated high resistivity (4-6 kOMEGA-cm) silicon detectors in the neutron fluence (PHI(n)) range of 5 X 10(11) n/cm2 to 1 X 10(14) n/cm2 have been studied using a laser deep level transient spectroscopy (L-DLTS). It has been found that the A-center (oxygen-vacancy, E(c) = 0.17 eV) concentration increases with neutron fluence, reaching a maximum at PHI(n) almost-equal-to 5 X 10(12) n/cm2 before decreasing with PHI(n). A broad peak has been found between 200 K and 300 K, which is the result of the overlap of three single levels: the V-V- (E(c) = 0.38 eV), the E-center (P-V, E(c) = 0.44 eV), and a level at E(c) = 0.56 eV that is probably V-V0. At low neutron fluences (PHI(n) < 5 X 10(12) n/cm2), this broad peak is dominated by V-V- and the E-centers. However, as the fluence increases (PHI(n) greater-than-or-equal-to 5 X 10(12) n/cm2), the peak becomes dominated by the level of E(c) = 0.56 eV.

NEW TYPE OF SILICON MATERIAL WITH VERY HIGH-QUALITY SURFACE-LAYER ON INSULATING DEFECT LAYER

A new-type silicon material, silicon on defect layer (SODL) was proved to have a very high quality surface microstructure which is necessary for commercially feasible high-density very large scale integrated circuits (VLSI). The structure of the SODL material was viewed by transmission electron microscopy. The SODL material was also proved to have a buried defect layer with an insulating resistivity of 5.7 x 10(10) OMEGA-cm.

DEFECT MODEL OF PHOTOCONVERSION BY OXYGEN IN SEMIINSULATING GAAS

The basic idea of a defect model of photoconversion by an oxygen impurity in semi-insulating GaAs, proposed in an earlier paper, is described in a systematic way. All experiments related to this defect, including high-resolution spectroscopic measurements, piezospectroscopic study, and recent measurements on electronic energy levels, are explained on the basis of this defect model. The predictions of the model are in good agreement with the experiments. A special negative-U mechanism in this defect is discussed in detail with an emphasis on the stability of the charge states. The theoretical basis of using a self-consistent bond-orbital model in the calculation is also given.

METASTABLE DEFECT IN AMORPHOUS-SILICON SOLAR-CELLS INVESTIGATED BY JUNCTION RECOVERY TECHNIQUE

The effect of metastable defects caused by light soaking and carrier injection on the transport of carriers in undoped a-Si:H has been investigated by a junction recovery technique. The experiments show that after light soaking or carrier injection the product of mu-p-tau-p decreases, but no detectable change in the distribution of shallow valence band tail states was found.

DEVELOPMENT OF CURRENT-BASED MICROSCOPIC DEFECT ANALYSIS-METHODS AND ASSOCIATED OPTICAL FILLING TECHNIQUES FOR THE INVESTIGATION ON HIGHLY IRRADIATED HIGH-RESISTIVITY SILICON DETECTORS

Current based microscopic defect analysis methods such as current deep level transient spectroscopy (I-DLTS) and thermally stimulated current (TSC) have been further developed in accordance with the need for the defect analysis of highly irradiated (Phi(n) > 10(13) n/cm(2)) high resistivity silicon detectors. The new I-DLTS/TSC system has a temperature range of 8 K less than or equal to T less than or equal to 450 K and a high sensitivity that can detect a defect concentration of less than 10(10)/cm(3) (background noise as low as 10 fA). A new filling method using different wavelength laser illumination has been applied, which is more efficient and suitable than the traditional voltage pulse filling. It has been found that the filling of a defect level depends on such factors as the total concentration of free carriers generated or injected, the penetration length of the laser (laser wavelength), the temperature at which the filling is taking place, as well as the decay time after the filling (but before the measurement). The mechanism of the defect filling can be explained by the competition between trapping and detrapping of defect levels, possible capture cross section temperature dependence, and interaction among various defect levels in terms of charge transferring. Optimum defect filling conditions have been suggested for highly irradiated high resistivity silicon detectors.

Energy level analyses of even-parity J=1 and 2 Rydberg states of Sn I by multichannel quantum defect theory

This paper analyzes the energy levels along the even-parity J=1 and 2 Rydberg series of Sn I by multichannel quantum defect theory. A good agreement between theoretical and experimental energy levels was achieved. Below 59198 cm~(-1), a total of 85 and 23 new energy levels, respectively, in the J=1 and J=2 series, which cannot be measured previously by experiments, are predicted in this work. Based on the calculated admixture coefficients of each channel, interchannel interactions were discussed in detail. The results are helpful to understand the characteristics of configuration interaction among even-parity levels in Sn I.

Defect Cluster-Induced X-Ray Diffuse Scattering in GaN Films Grown by MOCVD

High-resolution X-ray diffraction has been employed to investigate the diffuse scattering in a (0001) oriented GaN epitaxial film grown on sapphire substrate. The analysis reveals that defect clusters are present in GaN films and their concentration increases as the density of threading dislocations increases. Meanwhile, the mean radius of these defect clusters shows a reverse tendency. This result is explained by the effect of clusters preferentially forming around dislocations, which act as effective sinks for the segregation of point defects. The electric mobility is found to decrease as the cluster concentration increases.