磁通量子比特qubit信号强度随势垒偏置电压的变化

在20mK极低温下,测量了超导磁通量子比特的环流方向,并测到量子比特(qubit)信号.通过改变磁通量子比特的势垒高度,得到qubit信号强度随势垒高度的变化的实验数据并建立理论模型解释了实验现象.     

The influence and explanation of fringing-induced barrier lowering on sub-100 nm MOSFETs with high-k gate dielectrics

The fringing-induced barrier lowering(FIBL) effect of sub-100 nm MOSFETs with high-k gate dielectrics is investigated using a two-dimensional device simulator.An equivalent capacitance theory is proposed to explain the physics mechanism of the FIBL effect.The FIBL effect is enhanced and the short channel performance is degraded with increasing capacitance.Based on equivalent capacitance theory,the influences of channel length,junction depth,gate/lightly doped drain(LDD) overlap length,spacer material and spacer width on FIBL is thoroughly investigated.A stack gate dielectric is presented to suppress the FIBL effect.     

Coverage Dependence of Growth Mode in Heteroepitaxy of Ni on Cu（100） Surface

A realistic kinetic Monte Carlo （KMC） simulation model with physical parameters is developed, which well reproduces the heteroepitaxial growth of multilayered Ni thin film on Cu（100） surfaces at room temperature. The effects of mass transport between interlayers and edge diffusion of atoms along the islands are included in the simulation model, and the surface roughness and the layer distribution versus total coverage are calculated. Speeially, the simulation model reveals the transition of growth mode with coverage and the difference between the Ni heteroepitaxy on Cu（100） and the Ni homoepitaxy on Ni（100）. Through comparison of KMC simulation with the real scanning tunneling microscopy （STM） experiments, the Ehrlich-Schwoebel （ES） barrier Ees is estimated to be 0.18±0.02 eV for Ni/Cu（100） system while 0.28 eV for Ni/Ni（100）. The simulation also shows that the growth mode depends strongly on the thickness of thin film and the surface temperature, and the critical thickness of growth mode transition is dependent on the growth condition such as surface temperature and deposition flux as well.     

Effect of Ca interlayer thickness on electron injection of lithium quinolate/Ca/Al cathodes

Electron injection behavior of lithium quinolate (Liq)/Ca/Al cathode was investigated by using X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy (UPS). Interfacial energy barrier lowering of Liq/Ca/Al cathode was dependent on Ca thickness and maximum energy level shift was observed at a Ca thickness of 1 nm. Maximum current density could be obtained in Liq/Ca/Al device at a Ca thickness of 1 nm and it was well correlated with energy level shift from UPS measurement. Power efficiency of Liq/Al device could be improved by more than 70% by inserting Ca layer between Liq and Al.     

量子阱垒层掺杂变化对双波长LED调控作用研究

采用APSYS软件研究了InGaN/GaN量子阱垒层掺杂变化对双波长 发光二极管发光光谱的调控问题. 在不同掺杂类型和浓度下对器件电子空穴浓度分布、 载流子复合速率、 能带结构、 发光光谱进行分析, 结果表明, 调节量子阱垒层n型和p型的掺杂浓度可以精确而有效地根据需要调控发光光谱, 解决发光光谱调控难的问题. 这些现象归因于掺杂的量子阱垒层对电子空穴分布的调控作用.     

狭缝光栅、柱面透镜光栅及其新构型在三维显示中的应用

介绍了三维显示技术的研究现状,综述了狭缝光栅和柱面透镜光栅在自由立体显示技术中的重要应用。回顾了各种光栅式自由立体显示系统的结构和原理;提出了如何根据狭缝光栅和柱面透镜光栅的特殊光学性质,在传统的立体显示系统中添加各种光栅形成灵活组合结构来提高立体显示效果,强调了它们在减小串扰、增大视场角、避免摩尔条纹以及提供更全面的三维信息等方面的作用。最后指出基于两种光栅的叠加构成面积大、参数均匀、价格低廉的新型透镜可实现全视差立体显示,对探索自由立体显示技术的研究很有意义。     

Influence of pores on the surface microcompression mechanical response of thermal barrier coatings fabricated by atmospheric plasma spray—Finite element simulation

Surface microcompression is a very important technique to characterize the mechanical properties of film and coating systems. In this paper, surface microcompression simulation for La₂Zr₂O₇ (LZ) thermal barrier coatings (TBCs) was implemented by finite element method, especially, the influence of pores on the surface microcompression mechanical response of the thermal barrier coatings fabricated by atmospheric plasma spray (APS) was focused on. The simulation results indicate that the pores not only affect the stress distribution beneath the contact area between the indenter and coating surface, but also affect the shape of the force-displacement curve and the plastic deformation behavior of TBCs. The micromechanism was discussed in detail in this study. At the same time, by using the surface microcompression technique, a new direction or method was proposed to characterize the pore content of the coating quantitatively.     

肖特基结的制备与势垒测量

采用磁控溅射方法在Nb07％-SrTiO3基片上制作Au薄膜接触,并在氧气气氛下750℃退火30 min,在室温环境下测量电流电压和电容电压等特性曲线,观测整流特性,根据相应实验数据采用饱和电流法、电容C-2与反偏电压V成线性关系计算肖特基势垒的大小.     

Electroluminescence efficiency in bilayer organic light-emitting devices with LiF/Al cathode

An analytical model to calculate electroluminescence (EL) efficiency of bilayer organic light-emitting devices, considering the influence of introducing LiF insulating buffer layer at metal/organic interface on the barrier height for electron injection, was presented. The relations of EL efficiency versus the applied voltage and injection barrier or internal interfacial barrier or the thickness of organic layer were discussed. The results indicate that: (1) when δ e/δ h < 2, metal/organic (M/O) interface is ohmic contact; when δ e/δ h > 2, M/O becomes contact limited; and when δ e/δ h = 2 (Φ h ～ 0.2 eV, Φ e ～ 0.3 eV), there is a transition from ohmic contact to contact limited; (2) η EL decreases with the increase of δ′e / δ′h; however, when δ′e / δ′h > 2.5 (H ′h～ 0.2 eV, H ′e～ 0.4 eV), the changes of η EL are very small, which shows that η EL is dominated by the carrier’s injection; (3) when increasing Lh/L, η R has a descending trend at low voltage and a rising one at higher voltage. For a given Lh/L, η EL first increases and then decreases with the increasing applied voltage, and as Lh/L further increases, the variation tendency of η EL is more obvious. These conclusions are in agreement with the reported theoretic and experimental results.     

Deposition of SiOx barrier films by O2/TMDSO RF-PECVD

This paper reports that the SiOx barrier films are deposited on polyethylene terephthalate substrate by plasmaenhanced chemical vapour deposition （PECVD） for the application of transparent barrier packaging. The variations of 02/Tetramethyldisiloxane （TMDSO） ratio and input power in radio frequency （RF） plasma are carried out to optimize barrier properties of the SiOx coated film. The properties of the coatings are characterized by Fourier transform infrared, water vapour transmission rate （WVTR）, oxygen transmission rate （OTR）, and atomic force microscopy analysers. It is found that the 02/TMDSO ratio exceeding 2：1 and the input power over 200 W yield SiOx films with low carbon contents which can be good to the barrier （WVTR and OTR） properties of the SiOx coatings. Also, the film properties not only depend on oxygen concentration of the inlet gas mixtures and input power, but also relate to the surface morphology of the coating.