Performance comparison of Pt/Au and Ni/Au Schottky contacts on AlxGa1-x N/GaN heterostructures at high temperatures

In contrast with Au/Ni/Al 0.25 Ga 0.75 N/GaN Schottky contacts,this paper systematically investigates the effect of thermal annealing of Au/Pt/Al 0.25 Ga 0.75 N/GaN structures on electrical properties of the two-dimensional electron gas in Al 0.25 Ga 0.75 N/GaN heterostructures by means of temperature-dependent Hall and temperature-dependent current-voltage measurements.The two-dimensional electron gas density of the samples with Pt cap layer increases after annealing in N 2 ambience at 600℃ while the annealing treatment has little effect on the two-dimensional electron gas mobility in comparison with the samples with Ni cap layer.The experimental results indicate that the Au/Pt/Al 0.25 Ga 0.75 N/GaN Schottky contacts reduce the reverse leakage current density at high annealing temperatures of 400-600℃.As a conclusion,the better thermal stability of the Au/Pt/Al 0.25 Ga 0.75 N/GaN Schottky contacts than the Au/Ni/Al 0.25 Ga 0.75 N/GaN Schottky contacts at high temperatures can be attributed to the inertness of the interface between Pt and AlxGa1-xN.     

Al_xGa_(1-x)As:Si中DX中心的双极化子机制及统计分析

基于极化子和双极化子的物理图像,采用无拟合参数的巨正则统计方法计算了Si掺杂的AlxGa1-xAs的导带载流子浓度,计算得到的理论结果从高温到低温都与实验结果定量一致.计算证实了AlxGa1-xAs:Si中的DX中心的基态DX-是电子-晶格相互作用产生的负电双极化子.处于热平衡状态时,施主Si在AlxGa1-xAs中除了电离状态,处于不同晶格构型的单、双极化子态共存,低温时双极化子态被冻结;光照下发生持续光电导时,双极化子态变成单极化子态同时向导带释放一个电子,此过程伴随着进一步的晶格弛豫.理论与实验的对照说明单电子局域的DX0态在热平衡时并不能稳定存在,这和提出的双极化子机制是完全一致的.     

机场新增卫星厅对登机口影响的评估方法

为了解决航站楼客流量饱和的问题,采用一种增加卫星厅的方法,实现了旅客分流.基于单目标整数线性规划和多目标优化的方法,分别构建了登机口优化分配网络模型和多目标优化模型.利用登机口优化分配网络算法筛选出所使用的共同登机口,建立了目标函数并列出约束条件,采用目标约束法对建立的模型进行求解.在此基础上,根据目标建模的思想,建立了可供中转旅客总体流程时间最短且使用登机口数量最小的航班-登机口分配模型.利用MATLAB计算可知,利用42个登机口即可实现303架航班的正常运转.     

利用二粒子部分纠缠态实现开靶目标的非局域量子可控非（CNOT）门的受控操作

提出利用二粒子部分纠缠态概率性地实现开靶目标的非局域量子可控非（CNOT）门的操控方案.首先考虑利用3个二粒子部分纠缠态实现3个靶目标共享的非局域量子CNOT门的受控操作,然后将该方案推广到N个靶目标共享的情形. 在该方案中,控制端Alice的局域正定算符值测量（POVM）起着关键作用,给出了该测量算符的数学表式.值得注意的是, 用二粒子部分纠缠态可确定性地实现非局域CNOT门. 关键词： 二粒子部分纠缠态 非局域可控非门 开靶目标 正定算符值测量     

Resistor-transistor logic circuits using vertical-type organic transistors

NOR gate operation using organic devices was demonstrated based on resistor-transistor logic (RTL). The RTL was composed of an OR gate using two single layered devices as input resistors and a NOT gate (inverter) using a vertical-type metal base organic transistor (MBOT). The input resistors were connected to the base electrode of the MBOT. When either input was turned from low to high voltage, the output voltage changed from high to low, indicating NOR operation. Dynamic characteristics of the RTL circuit was also evaluated, and operation frequency was estimated to be 300 Hz.     

偏置条件对SOINMOS器件总剂量辐照效应的影响

本文研究了0．8μmSOINMOS晶体管，经剂量率为50rad（Si）／s的60Coγ射线辐照之后的总剂量效应，分析了器件在不同辐照条件和测量偏置下的辐照响应特性．研究结果表明：器件辐照时的栅偏置电压越高，辐照后栅氧化层中积累的空穴陷阱电荷越多，引起的漏极泄漏电流越大．对于漏偏置为5V的器件，当栅电压大于阈值电压时，前栅ID-VG特性曲线中的漏极电流因碰撞电离而突然增大，体电极的电流曲线呈现倒立的钟形．     

Two D-π-A type fluorescent probes based on isolongifolanone for sensing acidic pH with large Stokes shifts

Two novel isolongifolanone derivatives (2–3) with D-π-A configuration, which had a N,N-dimethylaniline unit attached to pyrazole and pyrimidine cores, were synthesized and characterized by IR, NMR and HRMS. As the protonation of the nitrogen atoms, the probes 2–3 displayed the significant pH-dependent spectral properties. The probe 2 exhibited a remarkable ratiometric fluorescence emission (I₄₄₅/I₃₇₃) characteristic with pK_a 2.59 and the linear response over the extremely acidic range of 1.5–4.0. The probe 3 showed an obvious emission quenching at 434?nm (λ_ex?=?300?nm) with a pK_a of 3.69 and responded linearly to monitor the pH fluctuations with the weakly acidic range of 3.5–7.0, while exhibited a linear emission enhancement at 519?nm (λ_ex?=?425?nm) over the extremely acidic range of 1.0–3.5. These pH probes also displayed favorable features including large Stokes shift under acidic conditions, high selectivity, rapid response, excellent photostability and good reversibility for sensing acidic pH which were further applied to response to acidic solid and gas phase using their solid-state samples, causing dramatic fluorescence color changes. In addition, the logic gates for probe 2 were constructed to develop its potential for practical applications.     

AlGaAs/InGaAs PHEMT栅电流参数退化模型研究

为定量研究在PHEMT栅电流退化过程中, 不同失效机理对应的参数退化时间常数及退化比例, 本文基于退化过程中物理化学反应中反应量浓度与反应速率的关系, 建立了PHEMT栅电流参数退化模型. 利用在线实验的方法获得PHEMT电学参数的退化规律, 分析参数随时间的退化规律, 得到不同时间段内影响栅电流退化的失效机理, 并基于栅电流参数退化模型, 得到了不同的失效机理对应的参数退化时间常数及退化比例. 关键词： PHEMT 栅电流 肖特基接触 退化模型     

Deterministic CNOT gate and entanglement swapping for photonic qubits using a quantum-dot spin in a double-sided optical microcavity

Abstract We propose a deterministic and scalable scheme to construct a two-qubit controlled-NOT (CNOT) gate and realize entanglement swapping between photonic qubits using a quantum-dot (QD) spin in a double-sided optical microcavity. The scheme is based on spin selective photon reflection from the cavity and can be achieved in a nondestructive and heralded way. We assess the feasibility of the scheme and show that the scheme can work in both the weak coupling and the strong coupling regimes. The scheme opens promising perspectives for long-distance photonic quantum communication and distributed quantum information processing.