Design and fabrication of normal incidence p-type SiGe/Si quantum well infrared photodetector

量子阱红外探测器（QWIP）在国防、工业、医疗等方面具有广泛的应用前景。受量子力学跃迁选择定则的限制，传统n型量子阱红外探测器对正入射光的吸收是禁戒的，需要制作复杂的光栅耦合正入射光。而p型QWIP具有能对正入射光响应的特点，且具有更低的暗电流，引起人们的广泛关注。其中，p型SiGe/SiQWIP与硅微电子工艺兼容，可直接制作在硅读出电路上，易于实现光电器件的单片集成。因此，p型SiGe/SiQWIP的研究具有诱人的前景。 本论文主要开展了以下几个方面的工作： （1）采用6×6方法计算应变SiGe/Si量子阱的价带能带结构。分析空穴子带能级随阱宽和Ge组分的变化规律，讨论基于束缚态到准束缚...Quantum well infrared photodetectors (QWIPs) offer numerous potential applications in defense, industry and medicine. For conventional n-type QWIPs, special optical couplers such as gratings are always required to detect normal incidence because the transition is forbidden by the quantum mechanical selection rules. Whereas, the p-type QWIPs are sensitive to normally incident radiation and have low...学位：理学硕士院系专业：物理与机电工程学院物理学系_凝聚态物理学号：2005130164

An Energy Band Design for p-Type Tensile Strained Si/SiGe Quantum Well Infrared Photodetectors

提出p型张应变Si/SiGe量子阱红外探测器(QWIP)结构,应用k.p方法计算应变Si/SiGe量子阱价带能带结构和应变SiGe合金空穴有效质量.结果表明量子阱中引入张应变使轻重空穴反转,基态为有效质量较小的轻空穴态,因此p型张应变Si/SiGe QWIP与n型QWIP相比具有更低的暗电流;而与p型压应变或无应变QWIP相比光吸收和载流子输运特性具有较好改善.在此基础上讨论了束缚态到准束缚态子带跃迁型张应变p-Si/SiGe QWIP的优化设计.Quantum well infrared photodetectors(QWIPs)offer numerous potential applications for defense,industry,and medicine.A novel p-type tensile strained Si/SiGe QWIP is proposed in this paper.The valence band structure of the strained Si/SiGe quantum well and hole effective mass of the strained SiGe alloy are calculated using the k·p method.When tensile strain is induced in the quantum wells,the light-hole state with small effective mass becomes the ground state,which is expected to have lower dark current than n-type QWIPs and also have larger absorption coefficient and better transport characteristics than conventional unstrained or compressive strained p-type QWIPs.Designs for p-type tensile strained Si/SiGe QWIP based on the bound-to-quasi-bound transitions are also discussed.国家自然科学基金(批准号:50672079,60336010,60676027);; 国家重点基础研究发展规划(批准号:2007CB613400)资助项目~

Aripiprazole versus other atypical antipsychotics for schizophrenia

BACKGROUND: In most western industrialised countries, second generation (atypical) antipsychotics are recommended as first line drug treatments for people with schizophrenia. In this review we specifically examine how the efficacy and tolerability of one such agent - aripiprazole - differs from that of other comparable second generation antipsychotics. OBJECTIVES: To evaluate the effects of aripiprazole compared with other atypical antipsychotics for people with schizophrenia and schizophrenia-like psychoses. SEARCH METHODS: We searched the Cochrane Schizophrenia Group Trials Register (November 2011), inspected references of all identified studies for further trials, and contacted relevant pharmaceutical companies, drug approval agencies and authors of trials for additional information. SELECTION CRITERIA: We included all randomised clinical trials (RCTs) comparing aripiprazole (oral) with oral and parenteral forms of amisulpride, clozapine, olanzapine, quetiapine, risperidone, sertindole, ziprasidone or zotepine for people with schizophrenia or schizophrenia-like psychoses. DATA COLLECTION AND ANALYSIS: We extracted data independently. For dichotomous data we calculated risk ratios (RR) and their 95% confidence intervals (CI) on an intention-to-treat basis based on a random-effects model. Where possible, we calculated illustrative comparative risks for primary outcomes. For continuous data, we calculated mean differences (MD), again based on a random-effects model. We assessed risk of bias for each included study. MAIN RESULTS: We included 12 trials involving 6389 patients. Aripiprazole was compared to olanzapine, risperidone and ziprasidone. All trials were sponsored by an interested drug manufacturer. The overall number of participants leaving studies early was 30% to 40%, limiting validity (no differences between groups).When compared with olanzapine no differences were apparent for global state (no clinically important change: n = 703, 1 RCT, RR short-term 1.00 95% CI 0.81 to 1.22; n = 317, 1 RCT, RR medium-term 1.08 95% CI 0.95 to 1.22) but mental state tended to favour olanzapine (n = 1360, 3 RCTs, MD total Positive and Negative Syndrome Scale (PANSS) 4.68 95% CI 2.21 to 7.16). There was no significant difference in extrapyramidal symptoms (n = 529, 2 RCTs, RR 0.99 95% CI 0.62 to 1.59) but fewer in the aripiprazole group had increased cholesterol levels (n = 223, 1 RCT, RR 0.32 95% CI 0.19 to 0.54) or weight gain of 7% or more of total body weight (n = 1095, 3 RCTs, RR 0.39 95% CI 0.28 to 0.54).When compared with risperidone, aripiprazole showed no advantage in terms of global state (n = 384, 2 RCTs, RR no important improvement 1.14 95% CI 0.81 to 1.60) or mental state (n = 372, 2 RCTs, MD total PANSS 1.50 95% CI -2.96 to 5.96).One study compared aripiprazole with ziprasidone (n = 247) and both the groups reported similar change in the global state (n = 247, 1 RCT, MD average change in Clinical Global Impression-Severity (CGI-S) score -0.03 95% CI -0.28 to 0.22) and mental state (n = 247, 1 RCT, MD change PANSS -3.00 95% CI -7.29 to 1.29).When compared with any one of several new generation antipsychotic drugs the aripiprazole group showed improvement in global state in energy (n = 523, 1 RCT, RR 0.69 95% CI 0.56 to 0.84), mood (n = 523, 1 RCT, RR 0.77 95% CI 0.65 to 0.92), negative symptoms (n = 523, 1 RCT, RR 0.82 95% CI 0.68 to 0.99), somnolence (n = 523, 1 RCT, RR 0.80 95% CI 0.69 to 0.93) and weight gain (n = 523, 1 RCT, RR 0.84 95% CI 0.76 to 0.94). Significantly more people given aripiprazole reported symptoms of nausea (n = 2881, 3 RCTs, RR 3.13 95% CI 2.12 to 4.61) but weight gain (7% or more of total body weight) was less common in people allocated aripiprazole (n = 330, 1 RCT, RR 0.35 95% CI 0.19 to 0.64). Aripiprazole may have value in aggression but data are limited. This will be the focus of another review. AUTHORS' CONCLUSIONS: Information on all comparisons are of limited quality, are incomplete and problematic to apply clinically. Aripiprazole is an antipsychotic drug with a variant but not absent adverse effect profile. Long-term data are sparse and there is considerable scope for another update of this review as new data emerges from the many Chinese studies as well as from ongoing larger, independent pragmatic trials