一种基于片上测试系统的AlGaN/GaN HEMT器件大信号建模方法

AlGaN/GaN材料是目前最吸引人的半导体材料之一。AlGaN/GaN高电子迁移率晶体管(HEMT)器件的建模方法主要基于传统的GaAs FET模型分析方法,未考虑材料本身的新特性。通过使用片上测试系统,结合数值分析方法,提出了一种AlGaN/GaN HEMT器件的大信号模型,该模型中的寄生参数值可通过特殊测试结构和数值优化方法获得,模型中的直流参数可以通过改进传统STATZ直流模型获得,改进后模型的直流参数随着栅-源电压的变化而变化,比传统STATZ模型准确度提高了约10%。实验测量结果表明,在0.1~40GHz的频率范围内,模型参数提取结果与器件测量结果吻合良好。     

AlInGaN/GaN异质结构材料生长及特性研究

AlInGaN四元合金具有独立控制禁带宽度和晶格常数的特性,利用这一特性可以实现性能更为出色的异质结构材料．利用MOCVD技术生长获得了AlInGaN／GaN异质结构,通过汞探针C—V测量和Hall效应测量,发现其电学特性明显优于常规AlGaN／GaN异质结构,通过XDR和AFM分析,发现其势垒层结晶质量十分出色,但表面形貌与常规异质结构相比还存在一定差距．     

高k栅介质厚度对MOS器件特性影响的数值模拟研究

展开了高k栅介质厚度对MOS器件特性影响的数值模拟研究.利用有限元数值分析手段,分析了栅介质厚度对MOS管驱动电流和阈值电压的影响,得到在不同栅介质厚度值情况下对应的输出特性曲线和转移特性曲线以及不同k值下的漏端电流.结果表明,减小栅介质层厚度,MOS管的驱动电流持续增加,阈值电压也显著下降.同时,在一定范围内随着k值的增大MOS管的漏端电流持续增加.     

发光层厚度对红光磷光聚芴电致发光性能的影响

文章采用喹啉氮杂环类锒配合物[（PPQ）2Ir（acac）]为客体,以聚芴和2-（4-二苯基）-5-（4-叔丁基苯基）-1,3,4-噁二唑（PBD）为主体,研究了不同发光层厚度对有机电致发光器件性能的影响．随着发光层厚度的增加,相同电压下器件的电流密度和发光亮度逐步减小,表现出明显的电荷捕获机制．当厚度达到70nm时,得到了发光亮度为1792cd／m^2,发光效率为6．16cd／A的高性能红光器件．     

利用KCl／Al作为电极的有机电致发光器件

制备了利用KCl／Al作为负电极的有机电致发光器件,器件结构为IT0／NPB／Alq／KCl／Al,KCl层的加入增强了电子注入,当其厚度为1．5nm时,器件的性能最好．与单层Al电极的同类器件相比,此时器件的开启电压由Al电极时的5V降低到了2．5V。器件的亮度在11V时由231cd／m^2提高到15070cd／m^2,器件的发光效率也增加了10倍,达到2．79cd／A．     

电子传输层改善磷光染料聚合物电致发光二极管

试验制作了以TPBI作为电子传榆层,以不同浓度磷光染料（PPQ）2Ir（acac）掺杂聚芴作为发光层的器件,研究了电子传输层对红光磷光染料聚合物器件的发光性能影响．器件的电流密度一电压的特性,发光亮度一电压特性,器件电致发光光谱发光效率一电流密度特性表明电子传输层的引入可以显著降低器件的工作电压和提高发光效率．这些性能的提高是由于TPBI有效的空穴阻挡作用．     

CTAB／正丁醇／正戊烷／水微乳液体系结构参数的测定

采用稀释法计算了CTAB／正丁醇／正戊烷／水的微乳体系的结构参数和醇由连续相转移到界面层的自由能变化．结果表明：随着随ω的增大,水内核半径Rw、界面层厚度,以及表面活性荆和醇在微乳粒子表面的平均聚集数n^-增加,而醇转移自由能-△G c→i、分散相所占总界面面积Ad和颗粒总数心减小．     

GaN基LED电流扩展效应的研究进展

与传统光源相比,GaN基发光二级管（LED）具有寿命长、节能、功耗低等优点,而优化LED有源区内电流扩展均匀性是提高u1D器件性能的关键。对国内外与u1D电流扩展相关的文献进行研究和归纳分析,结果表明,n型GaN层、P型Clan层、p型透明导电层、电极形状、芯片尺寸和器件结构等因素都会影响uTD有源区内的电流扩展均匀性。     

单色光电流-电压特性测试在碲化镉太阳电池研究中应用

针对不同结构的碲化镉(CdTe)太阳电池,测试其单色光特性,并计算出不同波长下的收集效率。结果表明,高质量的高阻层能提高太阳电池短波区的收集效率,对提高长波段的收集效率有一定作用;背接触层能够明显在电池背部形成欧姆接触;适当的硫化镉(CdS)层的厚度能够改善窗口层的界面,提升电池的器件性能。通过该测试方法可以获得器件结构与器件性能之间关系,从而为进一步优化电池结构和制备工艺、提高太阳电池转换效率提供依据。     

硅基与蓝宝石衬底上的GaN-LEDs性能差异分析

在简要阐述硅基与蓝宝石衬底的GaN研究与发展基础上,就此两种不同衬底上GaN-LEDs性能进行了对比分析,并对这两种衬底上的LED进行了相应的表征实验。通过AFM和XRD等分析手段揭示了器件的结构特性,对器件性能(I-V和EL以及I-L测试)进行了相应的评价。通过分析相关实验数据得出:在电学特性与光学性能两方面,蓝宝石衬底上的LED均优于硅衬底上的LED。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…