Correlated and non-correlated growth kinetics of pentacene in the sub-monolayer regime

We present a study of the growth kinetics of pentacene monolayer islands on SiO₂ in the submonolayer regime by using Atomic Force Microscopy (AFM). Two distinct growth modes, namely correlated growth (CG) and non-correlated growth (NCG), have been identified by Voronoi tesselation. These two modes are characterized by different island growth kinetics. In the case of correlated growth, the average island size 〈A〉 scales with deposition time t i.e. 〈A〉 ∝ t whereas for non-correlated growth, 〈A〉 ∝ t². The CG and NCG regimes are defined by the level of re-evaporation which determines the capture zones around the islands: Wigner-Seitz cells for CG and coronas of width λ_D (λ_D is the mean diffusion distance on SiO₂ before re-evaporation) for NCG. A simple model is proposed to reproduce the experimental growth kinetics in both modes.     

一种基于能带工程设计的CaAsSb/InP异质结双极晶体三极管

异质结晶体三极管（HBT）的性能与其材料体系密不可分，利用能带工程可以大大优化器件的结构，提高器件性能，文章从分析HBT的能带结构及设计要求入手，介绍了一种利用能带工程设计的基于GaAsSb/InP材料体系的新型HBT器件的结构及其性能，分析了该器件与其它材料体系器件相比所具有的优异特性，说明了对HBT的各区材料，其带边的相对位置所起的重要作用，最后，文章还报道了近期的实验情况，说明了GaAsSb/InP体系HBT的实际性能与理论预言一致。     

Room-temperature flexible thin film transistor with high mobility

We report a room-temperature and high-mobility InGaZnO thin-film transistor on flexible substrate. To gain both high gate capacitance and low leakage current, we adopt stacked dielectric of Y₂O₃/TiO₂/Y₂O₃. This flexible IGZO TFT shows a low threshold voltage of 0.45 V, a small sub-threshold swing of 0.16 V/decade and very high field-effect mobility of 40 cm²/V. Such good performance is mainly contributed by improved gate stack structure and thickness modulation of IGZO channel that reduce the interface trap density without apparent mobility degradation.     

Simultaneous Determination of Multicomponents in Air Toxic Organic Compounds Using Artificial Neural Networks in Ftir Spectroscopy

The application of Artificial Neural Networks (ANNs) for nonlinear multivariate calibration using simulated FTIR data was demonstrated in this paper. Neural networks consisting of three layers of nodes were trained by using the back-propagation learning rule. Since parameters affect the performance of the network greatly, simulated data were used to train the network in order to get a satisfactory combination of all parameters. The mixtures of four air toxic organic compounds whose FTIR spectra are overlapped were chosen to evaluate the calibration and prediction ability of the network. The relative standard error (RSD%), the percent standard error of prediction samples (%SEP) and the percent standard error of calibration samples (%SEC) are used for evaluating the ability of the neural network.     

Monolithic integration of an AlGaN/GaN metalinsulator field-effect transistor with an ultra-low voltage-drop diode for self-protection

In this paper,we present a monolithic integration of a self-protected AlGaN/GaN metal-insulator field-effect transistor(MISFET).An integrated field-controlled diode on the drain side of the AlGaN/GaN MISFET features a selfprotected function for a reverse bias.This diode takes advantage of the recessed-barrier enhancement-mode technique to realize an ultra-low voltage drop and a low turn-ON voltage.In the smart monolithic integration,this integrated diode can block a reverse bias(> 70 V/μm) and suppress the leakage current(< 5 × 10-11 A/mm).Compared with conventional monolithic integration,the numerical results show that the MISFET integrated with a field-controlled diode leads to a good performance for smart power integration.And the power loss is lower than 50% in conduction without forward current degeneration.     

Low temperature radio-frequency transverse susceptibility measurements using a CMOS oscillator circuit

A transverse susceptibility (TS) measurement system based on a simple inverter CMOS cell oscillator cross-coupled to a LC tank is presented. The system has been implemented to operate at a Quantum Design Physical Properties Measurement System (PPMS). We introduce several improvements with respect to similar currently operating TS measurement equipments. The electronics have been redesigned to use CMOS transistors as active devices, which simplifies the circuit design and enlarge the tuning range, thus making the proposed electronic block more feasible, predictable, and precise. Additionally, we propose a newly designed sample holder, which facilitates the procedure to change a sample and improves reproducibility of the circuit. Our design minimizes the thermal leak of the measuring probe by one order of magnitude, allowing to measure from 1.8 K in standard PPMS systems, thanks to the use of a low temperature beryllium–copper coaxial cable instead of the conventional RG402 Cu coaxial cable employed in the insert for the PPMS in similar systems. The data acquisition method is also simplified, so that the measuring sequences are implemented directly in the PPMS controller computer by programming them in the Quantum Design MultiVu software that controls the PPMS. We present the test measurements performed on the system without sample to study the background signal and stability of the circuit. Measurements on a Gd₂O₃ calibrating sample yield to the estimation of the system sensitivity, which is found to be on the order of 10⁻⁶ emu. Finally, measurements on a TmCo₂ Laves phase sample with a ferrimagnetic transition temperature around 4 K are described, demonstrating that the developed system is well suited to explore interesting magnetic phenomena at this temperature scale.     

问题式教学法在有机化学实验教学中的应用

以正溴丁烷的制备为例,介绍了问题式教学法在有机化学实验教学中的应用。从教学过程和问题设计等方面讨论了问题式教学法的过程,并取得了良好的教学效果。     

A study of GaN MOSFETs with atomic-layer-deposited Al2O3 as the gate dielectric

Accumulation-type GaN metal-oxide-semiconductor field-effect transistors (MOSFETs) with atomic-layer-deposited Al₂O₃ gate dielectrics are fabricated. The device, with atomic-layer-deposited Al₂O₃ as the gate dielectric, presents a drain current of 260 mA/mm and a broad maximum transconductance of 34 mS/mm, which are better than those reported previously with Al₂O₃ as the gate dielectric. Furthermore, the device shows negligible current collapse in a wide range of bias voltages, owing to the effective passivation of the GaN surface by the Al₂O₃ film. The gate drain breakdown voltage is found to be about 59.5 V, and in addition the channel mobility of the n-GaN layer is about 380 cm²/Vs, which is consistent with the Hall result, and it is not degraded by atomic-layer-deposition Al₂O₃ growth and device fabrication.     

Temperature and drain bias dependence of single event transient in 25-nm FinFET technology

In this paper,we investigate the temperature and drain bias dependency of single event transient(SET) in 25-nm fin field-effect-transistor(FinFET) technology in a temperature range of 0-135°C and supply voltage range of 0.4 V-1.6 V.Technology computer-aided design(TCAD) three-dimensional simulation results show that the drain current pulse duration increases from 0.6 ns to 3.4 ns when the temperature increases from 0 to 135°C.The charge collected increases from 45.5 fC to 436.9 fC and the voltage pulse width decreases from 0.54 ns to 0.18 ns when supply voltage increases from 0.4 V to 1.6 V.Furthermore,simulation results and the mechanism of temperature and bias dependency are discussed.     

非色散红外吸收法测定地表水和废水中的总有机碳

用燃烧氧化 -非色散红外吸收法测定了杭州市辖区内的地表水、污水处理厂排水和不同行业工业废水中的总有机碳 (TOC)。结果表明 ,本法检出限为 0 .3mg/ L ,对于 TOC浓度在 6 .1— 12 0 mg/ L范围内水样的测定 ,相对标准偏差在 1.3%— 10 %之间。