共查询到20条相似文献,搜索用时 251 毫秒
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用高能离子注入(160keV)的方法对InAs/GaAs量子点结构进行掺杂,研究了不同退火工艺处理后量子点的光致发光和电学性能.相对于长时间退火,快速退火处理后的量子点发光通常较强.在相同的退火条件下,量子点发光峰位随着Mn注入剂量的增加,先是往高能量端快速移动,而后发光峰又往低能方向移动.后者可能是由于Mn原子进入InAs量子点,释放了InAs量子点中的应变所致.对于高注入剂量样品和长时间退火样品,变温电阻曲线在40 K附近会出现反常行为.
关键词:
离子注入
InAs/GaAs量子点
光致发光
团簇 相似文献
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采用自悬浮定向流技术制备银团簇纳米颗粒,理论分析了银团簇的成核机理与影响因素,实验研究了制备条件和工艺。结果表明:惰性气体的冷却效率、气体流速和压强、金属熔球的温度和大小是控制颗粒尺寸大小及分布的关键条件,制备粒径小于10 nm的团簇颗粒须采用氦气为载流气体;团簇颗粒流速越大,颗粒粒径越小,尺寸分布越窄,但颗粒生成数量越少。性能表征说明:制备的颗粒呈较规则的球形,为面心立方结构,分散均匀,表面纯净无氧化,粒径分布窄。理论与实验研究了银团簇纳米颗粒的光学吸收谱性质,证明表面等离子共振吸收峰与颗粒的尺寸有很强的相关性,随着颗粒尺寸的减小,由于量子尺寸效应,吸收峰将发生宽化和蓝移。 相似文献
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对掺有镉、硒、硫的玻璃在650—800℃退火4?h,生长了不同尺寸的CdS0.13Se0.87纳米晶体,测量了纳米晶体的吸收光谱、光致发光(PL)谱和电调制光谱,确定了纳米晶体部分电子态的能量,讨论了CdSSe纳米晶体的光学性质与其尺寸之间的依赖关系.随着纳米晶体尺寸的增大,对应激子的吸收峰、PL峰及电吸收信号发生红移,表现出明显的量子尺寸效应.小尺寸纳米晶体的电吸收表现为量子受限的Stark效应,而大尺寸纳米晶体的电吸收线形与体材料的相似;随着纳米晶体尺寸的增大,电吸收信号增强.所有尺寸的纳米晶体都表现
关键词:
CdSSe纳米晶体
吸收光谱
光致发光谱
电光响应 相似文献
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对掺有镉、硒、硫的玻璃在500—800℃退火2—24h,生长了不同尺寸的CdSxSe1x纳米晶体.用分光光度计和光致发光光谱(PL)分析了纳米晶体的性能.退火温度低于550℃,纳米晶体处于成核阶段,600—625℃处于正常扩散生长阶段,700—800℃处于竞争生长阶段;而650℃处于两种生长阶段之间.虽然650℃下生长的纳米晶体的尺寸分布比较窄,但纳米晶体的尺寸随退火时间的延长几乎不变,在该温度改变退火时间很难改变纳米晶体的平均尺寸.在所有样品中出现了深能级缺陷,在650℃退火时间小于4h或大于16h有利
关键词:
纳米晶体
生长机理
深能级缺陷 相似文献
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利用等离子体增强化学气相淀积技术,在绝缘氮化硅(SiNx)衬底上制备超薄非晶硅(aSi:H)薄膜,通过超短脉冲激光辐照与准静态常规热退火技术处理,制备出高密度、均匀纳米硅(ncSi)量子点.使用原子力显微镜对处理前后样品的表面形貌进行了研究,发现激光辐照能量密度增加的同时,所形成的ncSi尺寸也随之增加.在合适的能量密度范围内,可以得到面密度大于10.11cm^2、尺寸分布标准偏差小于20%的10 nm ncSi量子点薄膜,表明所制备的ncSi量子点具有较好的均匀性及较高的面密度.同时,对ncS i量子点
关键词:
纳米硅
激光诱导
尺寸分布 相似文献
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用导纳谱技术研究了两类Si基量子阱样品基态子能级的性质.基于量子阱中载流子的热激发模型,从导纳谱中得到的激发能值被认为是阱中重空穴基态位置到阱顶的距离.对于SiGe合金和Si形成的组分量子阱,主要研究了退火对重空穴基态子能级的影响.发现样品的退火温度为800℃时,随退火时间延长,激发能增加.对此现象的解释是,由于Si,Ge互扩散,导致界面展宽,量子限制效应降低,重空穴基态位置下降,从而激发能增加.900℃下退火,由于扩散系数增大和应变弛豫加强,激发能值单调下降,量子限制效应引起的变化被掩盖.对于B高浓度超
关键词: 相似文献
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This work deals with the optoelectronic properties of heterostructures built
on type II Si1-xGex/Si strained quantum wells grown on relaxed
Si1-yGey/Si (001) pseudo-substrates. To limit the intrinsic
problem due to the real-space indirect nature of the interface, we propose
and model three heterostructures having three different potential profiles
of the valence and conduction bands which consist in various arrangements of
Si and Si1-xGex barriers of different Ge contents. The proposed
stacks are designed in a pragmatic way for a pseudomorphic growth on relaxed
Si1-yGey assuming individual layer thickness being smaller than
the known critical thickness and an overall compensation of the strain.
Variation of thickness and compositions (x>y) permits to optimize i) the
quantum confinement of electrons and heavy-hole levels and ii) the wave
function's overlap and the out-of-plane oscillator strength. The optimum
parameters satisfy a fundamental emission at a key 1.55 μm wavelength
below the absorption edge of each layer constitutive of the stacks. A
comparison between the characteristics of the three heterostructures brings
out the superior advantages of the W architecture. 相似文献
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通过测量GeSi多量子阱的红外谱,同时观察到了相应于量子阱内重空穴基态HH1到重空穴激发态HH1、轻空穴激发态LH1和自旋分裂带SO及连续态间的跃迁吸收.测量了GeSi多量子阱探测器的正入射光电流谱,看到了明显的光响应峰.理论计算中计及了轻、重和自旋分裂带间的耦合及能带的非抛物性,并自洽考虑了哈特里势和交换相关势.与实验结果比较,认为带之间的耦合,使子带间的跃迁情况变得复杂,是正入射吸收产生的原因
关键词: 相似文献
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R. Turan B. Aslan O. Nur M.Y.A. Yousif M. Willander 《Applied Physics A: Materials Science & Processing》2001,72(5):587-593
We have studied the effect of the strain relaxation on the band-edge alignments in a Pt/p-Si1-xGex Schottky junction with x=0.14 by internal photoemission spectroscopy and current–voltage measurements. We have shown that
the variations in the band-edge alignments can be observed directly by measuring the optical and electrical properties of
a simple Schottky junction. The strain in the Si1-xGex layer has been partially relaxed by thermal treatments at two different temperatures. The degree of relaxation and other
structural changes have been determined by a high-resolution X-ray diffractometer. Both optical and electrical techniques
have shown that the barrier height of the Pt/Si0.86Ge0.14 junction increases with the amount of relaxation in the Si1-xGex layer. This shows that the valence-band edge of the Si1-xGex layer moves away from the Fermi level of the Pt/Si1-xGex junction. The band-edge movement results from the increase in the band gap of the Si1-xGex layer after the strain relaxation. This result agrees with the theoretical predictions for the strain-induced effects on
the Si1-xGex band structure.
Received: 18 October 2000 / Accepted: 19 December 2000 / Published online: 23 March 2001 相似文献
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Photoluminescence and transmission spectra of nanocrystalline GaAs(1-x)Sbx embedded in silica films 下载免费PDF全文
The composite films of the nanocrystMline GaAs(1-x)Sbx-SiO2 have been successfully deposited on glass and GaSb substrates by radio frequency magnetron co-sputtering. The 10K photoluminescence (PL) properties of the nanocrystalline GaAs(1-x)Sbx indicated that the PL peaks of the GaAs(1-x)Sbx nanocrystals follow the quantum confinement model very closely. Optical transmittance spectra showed that there is a large blue shift of optical absorption edge in nanocrystMline GaAs(1-x)Sbx-SiO2 composite films, as compared with that of the corresponding bulk semiconductor, which is due to the quantum confinement effect. 相似文献
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对分子束外延生长带边激子发光的Si1-xGex/Si量子阱结构,通过Si离子自注入和不同温度退火,观测到深能级发光带和带边激子发光的转变.Si离子注入量子阱中并在600℃的低温退火,形成链状或小板式的团簇缺陷,它导致深能级发光带的形成,在850℃的高温退火后重新观测到带边激子发光.这种团簇缺陷的热离化能约为0.1eV,比Si中空穴或填隙原子缺陷的热激活能(约0.05eV)高.这表明早期文献中报道的深能级发光带是由类似的团簇缺陷产生的.
关键词: 相似文献