微腔中nc-Si/SiN超晶格的光致发光

研究了一维光子晶体微腔结构对nc-Si/a-SiNz超晶格发射的调制.一维光子晶体微腔采用两种具有不同折射率的非化学组分非晶氮化硅的周期调制结构,腔中嵌入采用激光晶化方法制备的硅量子点阵列,从Raman谱和透射电子显微镜分析得到其尺寸约为3～4 nm.从光致发光谱上观察到明显的选模作用、明显变窄的发光峰以及约两个量级的发光强度的增强.微腔对硅量子点阵列发光的调制主要表现在两个方面:共振模式的增强和非共振模式的抑制.硅量子点中位于腔共振模式的辐射跃迁被增强,非共振模式的辐射跃迁被抑制,因此位于腔共振频率处的跃迁通道成为硅量子点中唯一的辐射跃迁通道,导致光致发光谱的窄化和强度的增强.因此,在提高硅材料发光效率方面,光子晶体微腔具有非常大的应用前景.     

微腔中nc-Si/SiN超晶格的光致发光

研究了一维光子晶体微腔结构对nc-Si/a-SiNz超晶格发射的调制. 一维光子晶体微腔采用两种具有不同折射率的非化学组分非晶氮化硅的周期调制结构，腔中嵌入采用激光晶化方法制备的硅量子点阵列，从Raman谱和透射电子显微镜分析得到其尺寸约为 3～4nm. 从光致发光谱上观察到明显的选模作用、明显变窄的发光峰以及约两个量级的发光强度的增强. 微腔对硅量子点阵列发光的调制主要表现在两个方面：共振模式的增强和非共振模式的抑制. 硅量子点中位于腔共振模式的辐射跃迁被增强，非共振模式的辐射跃迁被抑制，因此位于腔共振频率处的跃迁通道成为硅量子点中唯一的辐射跃迁通道，导致光致发光谱的窄化和强度的增强. 因此，在提高硅材料发光效率方面，光子晶体微腔具有非常大的应用前景.     

基于锗量子点的硅基发光器件

硅基光源是实现硅基集成光电子芯片的核心器件,虽然近年来国内外已经取得多项重要成果,但适合于下一代大规模光电集成芯片的小尺寸、低功耗、工艺兼容的高效硅基发光器件仍然缺乏。文章介绍了基于嵌入光学微腔中的锗量子点实现硅基发光器件方面的研究成果,通过将分子束外延生长的锗自组装量子点嵌入硅光子晶体微腔中,实现了室温下处于通信波段的共振发光。通过在图形化衬底上生长实现锗量子点的定位,并精确嵌入光子晶体微腔中,实现了基于锗单量子点的硅基发光器件。     

基于光子晶体渐变型双异构微腔的掺铒硅光致发光研究

实验验证了室温下二维氧化物下包层非对称平板三角晶格光子晶体渐变型双异构微腔对绝缘体上硅(SOI)基片上铒氧共掺硅材料的显著发光增强作用.在波长为488 nm、功率为15 mW激光激发下,微腔的光致发光(PL)谱呈现出一个位于1 557.93 nm通信波长处的尖锐狭窄的发光峰,相比于无光子晶体区域,发光增强了约13倍.谐振峰随光泵浦功率增加,发生明显的红移,Q值逐渐下降,在1.5mW光泵浦功率下,Q值达6 655.微腔谐振波长与光子晶体晶格周期之间呈线性正比关系,通过调整晶格周期,实现了掺铒硅发光增强峰波长的灵活可控.     

利用大周期光子晶体结构增强InAs/GaAs量子点的激发态发光

在该研究中,通过激光全息和湿法腐蚀的方法在InAs/GaAs量子点材料上制备光子晶体,研究了由激光二极管激发制备了光子晶体的InAs / GaAs量子点材料的光致发光光谱.发现具有光子晶体的量子点材料的光谱显示出多峰结构,光子晶体对短波长部分的发光增强和调制比对长波长部分的增强和调制更明显.InAs / GaAs量子点的光致发光光谱通过刻蚀形成的光子晶体结构得到了调控,并且量子点的激发态发光得到了明显增强.     

利用大周期光子晶体结构增强InAs/GaAs量子点的激发态发光（英文）

在该研究中,通过激光全息和湿法腐蚀的方法在InAs/GaAs量子点材料上制备光子晶体,研究了由激光二极管激发制备了光子晶体的InAs/GaAs量子点材料的光致发光光谱.发现具有光子晶体的量子点材料的光谱显示出多峰结构,光子晶体对短波长部分的发光增强和调制比对长波长部分的增强和调制更明显.InAs/GaAs量子点的光致发光光谱通过刻蚀形成的光子晶体结构得到了调控,并且量子点的激发态发光得到了明显增强.     

硅基法布里-珀罗微腔的室温发光

提出了一种新型基于法布里-珀罗(F-P)微腔的发光器件结构.它采用PECVD方法制备的非晶硅/二氧化硅结构作为微腔中的布拉格反射腔,非晶碳化硅薄膜作为中间光发射层,通过对一维方向光子的限制,使发光层荧光强度增强,谱线变窄.通过调节发光层和反射腔膜厚及折射率,可以精确控制发光峰位.实验结果证明该结构可望实现全硅基材料的强室温可见光发射.     

硅基法布里—珀罗微腔的室温发光

提出了一种新型基于法布里 -珀罗 (F- P)微腔的发光器件结构 .它采用 PECVD方法制备的非晶硅 /二氧化硅结构作为微腔中的布拉格反射腔 ,非晶碳化硅薄膜作为中间光发射层 ,通过对一维方向光子的限制 ,使发光层荧光强度增强 ,谱线变窄 .通过调节发光层和反射腔膜厚及折射率 ,可以精确控制发光峰位 .实验结果证明该结构可望实现全硅基材料的强室温可见光发射 .     

硅基法布里-珀罗微腔的室温发光

提出了一种新型基于法布里 -珀罗 (F- P)微腔的发光器件结构 .它采用 PECVD方法制备的非晶硅 /二氧化硅结构作为微腔中的布拉格反射腔 ,非晶碳化硅薄膜作为中间光发射层 ,通过对一维方向光子的限制 ,使发光层荧光强度增强 ,谱线变窄 .通过调节发光层和反射腔膜厚及折射率 ,可以精确控制发光峰位 .实验结果证明该结构可望实现全硅基材料的强室温可见光发射 .     

CdS纳米晶自组装形成的亚微米中空球微结构研究

Ⅱ-Ⅵ族半导体量子点（如GdS、CdSe等）,因其具有明显的量子尺寸将就和表面将就，近来成为人们研究的热点。以这些量子点为基元，可组装成许多有趣的结构，其中最具代表性的是被人们称为光子点的亚微米-微米尺度的中空球微腔结构。这种中空球微腔结构具有量子点和光子点耦合效应，可实现自发辐射的抑制和单模加强的量子点发光，称之为光子点对量子点发光的调制。     

Optical properties of a total-reflection-type one-dimensionalphotonic crystal

We produced an asymmetric Fabry-Perot microcavity using total reflection, and its optical properties were investigated. The structure is considered to be a total-reflection-type 1-D photonic crystal. An electric-field enhancement of incident light in a defect layer installed inside the photonic crystal was observed by fluorescence emission from dye molecules doped into the defect layer division. We confirmed that the incident light intensity was strengthened by about 63 times in the defect layer     

Size Control of Nanoscale Silicon Particles Formed in Thermally Annealed A- Si: H Films and Its Photoluminescence

A method to control the size of nanoscale silicon grown in thermally annealed hydrogenated amorphous silicon (a-Si : H) films is reported. Using the characterizing techniques of micro-Raman scattering,X-ray diffraction and computer simulation, it is found that the sizes of the formed silicon particles change with the temperature rising rate in thermally annealing the a-Si : H films. When the a-Si: H films have been annealed with high rising rate( ～ 100 C/s), the sizes of nanoscale silicon particles are in the range of 1.6～ 15nm. On the other hand, if the a-Si: H films have been annealed with low temperature rising rate(～1 C/s),the sizes of nanoscale silicon particles are in the range of 23～46 nm. Based on the theory of crystal nucleation and growth, the effect of temperature rising rate on the sizes of the formed silicon particles is discussed. Under high power laser irradiation, in situ nanocrystallization and subsequent nc-Si clusters are small enough for visible light emission, authors have not detected any visible photoluminescence(PL) from these nc-Si clusters before surface passivation. After electrochemical oxidization in hydrofluoric acid, however, intense red PL has been detected. Cyclic hydrofluoric oxidization and air exposure can cause subsequent blue shift in the red emission. The importance of surface passivation and quantum confinement in the visible emissions has been discussed.     

a-Si:H热处理过程中形成的纳米硅粒及其光致发光

报道了氢化非晶硅薄膜在600～620℃温度下快速退火10 s可以形成纳米晶硅,其拉曼散射表明,所形成的纳米晶硅在薄膜中的分布是随机的,其直径在1.6～15 nm内.根据晶体生长理论和计算机模拟,讨论了升温快慢与所形成纳米硅颗粒大小之间的关系,并且在强光照射下观察了纳米晶硅在薄膜中的结晶和生长情况.经退火形成的nc-Si可见光辐射较弱,不能检测到它们的光致发光,但用氢氟酸腐蚀钝化后则可检测到较强的红PL,并且钝化后的nc-Si在空气中暴露一定时间后,其辐射光波长产生了蓝移.就表面钝化和量子限制对可见光辐射的重要性作了讨论.     

Stable Temperature Characteristics of InAs／GaAs Quantum Dots at Long Wavelength Emission

The time-resolved photoluminescence and steady photoluminescence (TRPL and PL) spectra on self-assembled InAs/GaAs quantum dots (QDs) are investigated. By depositing GaAs/InAs short period superlattices (SLs), 1. 48μm emission is obtained at room temperature. Temperature dependent PL measurements show that the PL intensity of the emission is very steady. It decays only to half as the temperature increases from 15 K to room temperature, while at the same time, the intensity of the other emission decreases by a factor of 5 orders of magnitude. These two emissions are attributed to large-size QDs and short period superlattices (SLs), respectively. Large-size QDs are easier to capture and confine carriers, which benefits the lifetime of PL, and therefore makes the emission intensity insensitive to the temperature.     

光子晶体微腔发光二极管

光子晶体微腔因其具有增强自发辐射、定向输出和单模工作的能力而受到广泛关注。介绍了光子晶体微腔发光二极管的基本原理、设计、特性、制作及其典型器件。     

Size Control of Nanoscale Silicon Particles Formed in Thermally Annealed A-Si∶H Films and Its Photoluminescence

A method to control the si ze of nanoscale silicon grown in thermally annealed hydrogenated amorphous silico n (a-Si∶H) films is reported. Using the characterizing techniques of micro-Ra man scattering, X-ray diffraction and computer simulation, it is found that the sizes of the formed silicon particles change with the temperature rising rate i n thermally annealing the a-Si∶H films. When the a-Si∶H films have been anne aled with high rising rate( ~100 ℃/s), the sizes of nanoscale silicon particle s are in the range of 1.6~15 nm. On the other hand, if the a-Si∶H films have been annealed with low temperature rising rate(~1 ℃/s), the sizes of nanoscale silicon particles are in the range of 23~46 nm. Based on the theory of crystal nucleation and growth, the effect of temperature rising rate on the sizes of th e formed silicon particles is discussed. Under high power laser irradiation, in situ nanocrystallization and subsequent nc-Si clusters are small enough for vis ible light emission, authors have not detected any visible photoluminescence(PL) from these nc-Si clusters before surface passivation. After electrochemical ox idization in hydrofluoric acid, however, intense red PL has been detected. Cycli c hydrofluoric oxidization and air exposure can cause subsequent blue shift in t he red emission. The importance of surface passivation and quantum confinement i n the visible emissions has been discussed.     

Room-temperature light emission from an airbridge double-heterostructure microcavity of Er-doped Si photonic crystal

We experimentally demonstrate an efficient enhancement of luminescence from two-dimensional (2D) hexagonal photonic crystal (PC) airbridge double-heterostructure microcavity with Er-doped silicon (Si) as light emitters on siliconon-insulator (SOI) wafer at room temperature. A single sharp resonant peak at 1 529.6 nm dominates the photoluminescence (PL) spectrum with the pumping power of 12.5 mW. The obvious red shift and the degraded quality factor (Q-factor) of resonant peak appear with the pumping power increasing, and the maximum measured Q-factor of 4 905 is achieved at the pumping power of 1.5 mW. The resonant peak is observed to shift depending on the structural parameters of PC, which indicates a possible method to control the wavelength of enhanced luminescence for Si-based light emitters based on PC microcavity.     

激光干涉结晶法制备三维有序分布的nc-Si阵列

利用准分子激光干涉结晶法使a Si∶H/a SiNx∶H多层膜中的超薄a Si∶H层定域晶化 ,成功地制备出三维有序分布的nc Si阵列。原子力显微镜 (AFM )、微区拉曼 (micro Raman)光谱及剖面透射电子显微镜 (X TEM)的分析结果揭示在晶化薄膜中已形成平均尺寸约为 3 6nm ,横向周期 2 μm ,纵向周期与a Si∶H/a SiNx∶H多层膜周期 (14nm)相等的nc Si阵列。