Effects of Rapid Thermal Annealing on OpticalProperties of GaInNAs/ GaAs Single Quantum Well Grown by Plasma- Assisted Molecular Beam Epitaxy

国家自然科学基金,国家攀登计划

Light induced rapid thermal diffusion of boron atom in silicon

国家自然科学基金

Influence of the rapid thermal annealing on the properties of thin a-Si films

The variation of the structure, morphology and the electrical properties of thin amorphous silicon films caused by Rapid Thermal Annealing is studied. The films annealed at 1200degreesC for 2 minutes change their structure to polycrystalline and as a result their resistivity decreases by 4 orders of magnitude. Due to the small thickness of the as deposited amorphous silicon the obtained poly-Si is strongly irregular and has many discontinuities in its texture.

Selective intermixing of Ga(In)NAs/GaAs quantum well structures usingSiO(2) encapsulation and rapid thermal annealing

The quantum well intermixing of Ga(In)NAs/GaAs simple quantum well (SQW) using SiO2 encapsulation and rapid thermal annealing has been studied. Obvious enhanced intermixing of GaInNAs/GaAs SQW was observed due to the localized SiO2 capping layer and RTA at temperature between 650degreesC and 900degreesC. The selective intermixing strongly depends on N composition and In composition. An obvious selective intermixing had been found in the samples with small N composition and/or high In composition.

Effect of rapid thermal annealing on the Raman spectrum of Si0.33Ge0.67/Si (100) alloy

The effect of thermal annealing on the Raman spectrum of Si0.33Ge0.67 alloy grown on Si (100) by molecular beam epitaxy is investigated in the temperature range of 550-800 degrees C. For annealing below 700 degrees C, interdiffusion at the interface is negligible and the residual strain plays the dominant role in the Raman shift. The strain-shift coefficients for Si-Ge and Ge-Ge phonon modes are determined to be 915 +/- 215 cm(-1) and 732 +/- 117 cm(-1), respectively. For higher temperature annealing, interdiffusion is significant and strongly affects the Raman shift and the spectral shape.

Structural properties of polycrystalline silicon films formed by pulsed rapid thermal processing

A novel pulsed rapid thermal processing (PRTP) method has been used for realizing the solid-phase crystallization of amorphous silicon films prepared by PECVD. The microstructure and surface morphology of the crystallized films are investigated by X-ray diffraction (XRD) and atomic force microscopy (AFM). The results indicate that this PRTP is a suitable post-crystallization technique for fabricating large-area polycrystalline silicon films with good structural qualities such as large grain size, small lattice microstain and smooth surface morphology on low-cost substrate.

Effect of rapid thermal annealing on electron emission and DX centers in strained InGaAs/GaAs single quantum well laser diodes

nThermal processing of strained ln(0.2)Ga(0.8)As/GaAs graded-index separate confinement heterostructure single quantum well laser diodes grown by molecular beam epitaxy is investigated. It was found that rapid thermal annealing can improve the 77 K photoluminescence efficiency and electron emission from the active layer, due to removal of nonradiative centers from the InGaAs/GaAs interface. Because of the interdiffusion of Al and Ga atoms, rapid thermal annealing increases simultaneously the density of DX centers in the AlGaAs graded layer. The current stressing experiments of post-growth and annealed laser diodes are indicative of a corresponding increase in the concentration of DX centers, suggesting that DX centers may be responsible for the degradation of laser diode performance.

Rapid detection of porcine circovirus type 2 by loop-mediated isothermal amplification

A method of loop-mediated isothermal amplification (LAMP) was employed to develop a rapid and simple detection system for porcine circovirus type 2 (PCV2). The amplification could be finished in 60 min under isothermal condition at 64 degrees C by employing a set of four primers targeting the cap gene of PCV2. The LAMP assay showed higher sensitivity than the conventional PCR, with a detection limit of five copies per tube of purified PCV2 genomic DNA. No cross-reactivity was observed from the samples of other related viruses including porcine circovirus type 1 (PCV1), porcine parvovirus (PPV), porcine pseudorabies virus (PRV) and porcine reproductive and respiratory syndrome virus (PRRSV). The detection rate of PCV2 LAMP for 86 clinical samples was 96.5% and appeared greater than that of the PCR method. The LAMP assay reported can provide a rapid yet simple test of PCV2 suitable for laboratory diagnosis and pen-side detection due to ease of operation and the requirement of only a regular water bath or heat block for the reaction. (c) 2008 Elsevier B.V. All rights reserved.

Short columns with molecularly imprinted monolithic stationary phases for rapid separation of diastereomers and enantiomers

Three molecularly imprinted monolithic columns with different length but almost identical column volume had been prepared. It was observed that the separation factors of diastereomers and enantiomers were almost unaffected by column length. However, the short column with dimension of 38 mm x 8 mm W. showed much lower resistance to flow rate so that it could be operated at much higher flow rates. By combining stepwise gradient elution with elevated flow rate, the diastereomers of cinchonine and cinchonidine and the enantiomers of Cbz-DL-Trp and Fmoc-DL-Trp were successfully separated within 3 min on the short column with dimension of 38 mm. x 8 mm i.d.. Based on the above results, a cinchonine imprinted monolithic disk with dimension of 10 mm x 16 mm W. was further developed. The SEM image and the pore size distribution profile showed that large flow-through pores are present on the prepared monolith, which allowed mobile phase to flow through the disk with very low resistance. Chromatographic performances on the monolithic disk were almost unchanged compared with the long columns. A rapid separation of cinchonine and cinchonidine was achieved in 2.5 min at the flow rate of 9.0 ml/min. Furthermore, it was observed that there was almost no effect of the flow rate on the dynamic binding capacity at high flow rates. In addition, the effect of the loading concentration of analytes on the dynamic binding capacity, namely adsorption isotherm, was also investigated. A non-linear adsorption isotherm of cinchonine was observed on the molecularly imprinted monolith with cinchonine as template, which might be a main reason to result in the peak tailing of template molecule. (C) 2004 Elsevier B.V. All rights reserved.