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 .     

微腔结构顶发射有机白光器件

结合微腔效应,通过调节不同发光层的厚度制作了顶发射有机白光器件.器件结构为Si/Ag/Ag2O/m-MTDATA/NPB/DPVBi/DCJTB:Alq3/Alq3/LiF/Al/Ag,其中DPVBi,DCJTB与Alq3的掺杂层分别作为蓝光和红光发光层,在选定490 nm的谐振波长时,通过调节DPVBi和掺杂层的厚度来实现对器件发光色度的调节.当DPVBi厚度为1 nm,电压为9 V时,器件的色坐标为(0.33,0.34),非常接近白光等能点.此项工作为利用微腔效应制作高效率高亮度顶发射白光器件奠定了基础.     

具有微腔结构的有机顶发射电致发光器件的光谱分析

摘要: 制做了具有微腔结构的蓝色和白色有机顶发射电致发光器件。利用TBADN:3%DSAPh和Alq3:DCJTB/TBADN:TBPe/Alq3:C545材料为发光层,在玻璃基片上,依次制备薄膜：Ag为阳极反射层, CuPc作为空穴注入层,NPB作为空穴传输层,ITO为光程调节层; Al/Ag作为半透明阴极,电极的透射率在30%左右。通过改变ITO层的厚度,TBADN:3%DSAPh器件获得了深蓝色发光光谱,色坐标为(0.141, 0.049),半高宽为17nm发光光谱,实现了窄带发射,Alq3:DCJTB/TBADN:TBPe/Alq3:C545器件得到了不同颜色（红、蓝、绿）的发光光谱,实现了对光谱的调节作用。文章对微腔顶发射器件的发射强度和发光光谱半高宽的结果进行了分析。     

有机微腔蓝光发射二极管的研制

利用玻璃/DBR/ITO/NPB/NPB:二萘嵌苯/TAZ/Alq/Al器件结构,研制了有机微腔蓝光发射二极管.将激光染料二萘嵌苯掺于空穴传输材料NPB中作为发光层,Alq为电子传输层,为防止未参与复合的空穴到达金属电极,在NPB:二萘嵌苯和Alq之间引入一薄层TAZ,所研制的微腔器件的峰值位于456 nm,器件表现为较纯的蓝光发射,色坐标为x=0.165,y＝0.088.微腔器件的最大亮度为2 500 cd/m2,最大发光效率为0.23 cd/A.     

增强型有机半导体微腔发光器的研究

本文主要研究了有机半导体微腔发光增强性质的问题,微腔的发光层由空穴转移型对次苯基聚合物和电子转移型的染料掺杂8羟基喹啉铝质结构组成,通过调节Al和ITO电极之间有机聚合物层厚度达到微腔效应。研究结果表明这种结构的微腔极大地增强了电致发光效率。     

用有机混合物的方法优化微腔器件性能

制作了一种新型的有机电致微腔器件,将两种有机材料混合作为发光材料,通过简单改变两种材料的重量比,实现了微调腔长的目的,认为通过合理地调节两种材料的配比,可以实现微腔发光颜色的调节。两种配比的微腔器件均发出半宽很窄的双模发射(8和12 nm),而且调节两种材料的比例后所得光谱的谐振模式和强度均得到改变,但半宽却不变。另外,对比了传统异质结结构微腔和新型微腔的电流电压特性,发现通过将空穴传输材料和发光材料混合后,器件的开启电压得到了很大程度的降低(从7V降到4V)。     

用有机混合物实现对微腔电致发光光谱的调制

制做了一种新型的有机电致微腔器件，将两种有机材料混合作为发光材料，通过改变NPB和Alq的重量比(从1：28改变到17：1)，达到了调节腔长从而改变器件发光颜色的目的，且器件发光颜色不随所加电压变化；通过合理地调节两种材料的配比，可以实现微腔白光发射。5种配比的微腔器件均发出半宽度很窄的双模发射(8～12nm)；与传统的异质结微腔器件相比，开启电压从7V降到4V，亮度也得到了提高。     

串联白光OLED色温调整

白光有机电致发光器件(OLED)在实际应用中根据不同的应用场景而有不同的色温要求.该白光OLED具有串联混合结构,包括荧光蓝光发射单元和以Pt磷光材料为客体的黄光发光单元.利用串联器件中存在的弱微腔效应以及所用Pt磷光材料的掺杂特性,通过改变串联结构中空穴传输层的厚度、电荷产生层中n型结构的厚度、调整Pt磷光客体材料在...     

基于PEN柔性衬底的顶发射微腔OLED性能研究

设计了结构为Ag/MoOx空穴注入层(HIL)/有机层/LiF/Al/Ag/Alq3的柔性有机电致发光器件(FOLED),研究通过改变HIL层的厚度改变腔长实现对微腔效应的调节,制备了性能优化的微腔FOLED。通过器件性能的对比,得到了可用Ag作为反射阳极的顶发射微腔FOLED全彩显示器件优化结构,即蓝、绿和红FOLED对应的优化HIL层厚度分别为100nm、120nm和160nm。     

Spontaneous emission factor of a microcavity DBR surface-emittinglaser

The spontaneous emission factor (SEF) of a microcavity distributed Bragg reflector (DBR) surface-emitting laser has been obtained theoretically to investigate the possibility of the thresholdless lasing operation. Formulas expressing the spontaneous emission in a three-dimensional microcavity were obtained. By introducing the distribution of mode density in wavevector space, it is shown that the radiation pattern of spontaneous emission is deeply modified by the microcavity and is different from that in free space. Based on this result, the SEF and the emission lifetime are calculated as a function of emission spectral width and the size of the active region. It is found that the SEF exceeds 0.1, even though the spectral width is as large as 30 nm when the transverse size is smaller than 0.5 μm and the DBR reflectivity is larger than 90%     

Wavelength shift of selectively oxidized Al/sub x/O/sub y/-AlGaAs-GaAs distributed Bragg reflectors

The effect of multiple oxidations on Al/sub x/O/sub y/-GaAs DBRs and Al/sub x/O/sub y/-AlGaAs-GaAs DBRs is investigated. With a compositionally graded AlGaAs layer, the oxide DBR remains stable under thermal stress, whereas without it, the DBR fractures. The stopband of the oxide DBR with the AlGaAs layer shifts when sequenced through multiple oxidation processes, which is attributed to the vertical oxidation of the AlGaAs. The resonance wavelength of a Fabry-Perot cavity containing an oxide DBR shifts 6 nm after 30 min of additional oxidation at 425/spl deg/C.     

Microcavity effects in an external-cavity surface-emitting laser

Microcavity-induced lasing threshold reduction and modulation of the spontaneous emission coherence length with cavity length in an external-cavity resonant-periodic-gain, surface-emitting laser is reported. In contrast to comparing different epitaxial growths, external-cavity operation allows changing the cavity length without affecting material properties as well as arbitrarily long resonator lengths. The transition to the macrocavity domain is observed by extending the cavity length beyond the spontaneous emission coherence length. The maximum change in the spontaneous emission rate induced by the cavity QED effect in the presence of resonant periodic gain is calculated. As expected, for cavities longer than several wavelengths, microcavity Fabry-Perot resonance effects dominate over cavity QED in determining the cavity-normal spontaneous emission power and coherence length. A simple model of the cavity-normal spontaneous emission coherence length and spontaneous emission power emitted from a Gaussian source placed in an ideal Fabry-Perot cavity is consistent with our observations     

Sunlight-like white organic light-emitting diodes with inorganic/organic nanolaminate distributed Bragg reflector (DBR) anode microcavity by using atomic layer deposition

White organic light-emitting diodes (WOLED) with inorganic/organic/hybrid nanolaminate distributed Bragg reflector (DBR) prepared by atomic layer deposition (ALD) has been firstly developed, and the improved structural, optical, and electrical properties have been observed. The functional layer consists of periodically alternating layers of ZrO₂/Zircone (zirconium alkoxides with carbon-containing backbones) films fabricated using ALD. By well adjusting the thickness and emissive dyes of the emission layer, three white light diodes were realized based on three cavity modes with different resonance wavelength and intensity. The narrowed lectroluminescent (EL) spectra from the microcavity organic light emitting diodes (MOLEDs) are of high-purity, and the off-resonant optical mode is highly suppressed due to the excellent optical properties of the DBR layers with high reflectivity in a wide stop-band range. The CIE chromaticity coordinates of devices are tuned from (0.33, 0.34), (0.43, 0.40) to (0.57, 0.40), which are all on the planckian locus, and the color temperature is adjusted from 5783 K, 3842 K to 2245 K. This work exhibits a simple and novel approach to achieve a sunlight-like WOLED by constructing the inorganic/organic nanolaminate DBR using ALD, which will be very important for healthy display and lighting.     

The application of porous Si photonic crystals for metal-resonance enhanced fluorescence

This paper has demonstrated the resonance fluorescence enhancement of R6G when gold nanoparticles (Au NPs) deposited in the porous Si photonic crystal device. Both of microcavity (MC) and distributed Bragg reflector (DBR) with different parameters are investigated for making the photon transmission of photonic crystal device play an optimal role in enhancing fluorescence resonance. While minor changes were observed on the DBR substrates, a significant change in the intensity of enhanced fluorescence varies with the defect modes of MC substrates. Particularly, the strongest enhancement has been presented as the MC defect mode wavelength located at the maximum absorption wavelength of Au NPs. In this case, the fluorescence intensity of R6G on MC device is 2.5 times of that of R6G based on DBR device.     

Three-Dimensional FDTD Simulation of Micro-Pillar Microcavity Geometries Suitable for Efficient Single-Photon Sources

We present the results of calculations of the microcavity mode structure of distributed-Bragg-reflector (DBR) micro-pillar microcavities of group III-V semiconductor materials. These structures are suitable for making single photon sources when a single quantum dot is located at the center of a wavelength scale cavity. The 3-D finite difference time domain (FDTD) method is our primary simulation tool and results are validated against semi-analytic models. We show that high light extraction efficiencies can be achieved (>90%) limited by sidewall scattering and leakage. Using radial trench DBR microcavities or 2-D photonic crystal structures, we can further suppress sidewall emission, however, light is then redirected into other leaky modes     

Characteristics of a photonic bandgap single defect microcavityelectroluminescent device

A microcavity surface-emitting coherent electroluminescent device operating at room temperature under pulsed current injection is described. The microcavity is formed by a single defect in the center of a 2-D photonic crystal consisting of a GaAs-based heterostructure. The gain region consists of two 70-Å compressively strained In_0.15Ga_0.85As quantum wells, which exhibit a spontaneous emission peak at 940 nm. The maximum measured output power from a single device is 14.4 μW. The near-field image of the output resembles the calculated TE mode distribution in a single defect microcavity. The measured far-field pattern indicates the predicted directionality of a microcavity light source. The light-current characteristics of the device exhibit a gradual turn-on, or a soft threshold, typical of single- or few-mode microcavity devices. Analysis of the characteristics with the carrier and photon rate equations yields a spontaneous emission factor β≈0.06     

Spontaneous emission factor in post microcavity lasers

The first measurements of the spontaneous emission coupling efficiency (/spl beta/) for electrically pumped microcavity lasers with transverse photon confinement are reported. The influence of scattering losses and carrier diffusion on microcavity lasers is investigated, A /spl beta/ of 0.01 is measured at 126 K in a 3-/spl mu/m diameter device with optimal gain-cavity detuning.     

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