Photoluminescence investigation of the carrier confining propertiesof multiquantum barriers

A comparative luminescence study of two Ga_0.52In_0.48P-(Al_0.5Ga_0.5) _0.52In_0.48P single-quantum-well (SQW) samples with bulk and multiquantum barrier (MQB) barriers is presented. When excess carriers are only created in the quantum wells (QW's) of the samples by resonant excitation using a dye laser, the luminescence efficiency of both samples as a function of temperature is found to be essentially identical. We find, therefore, no evidence for any enhancement in the confining potential of the MQB sample over the bulk barrier sample. From Arrhenius plots of the integrated luminescence intensity, it is found that carrier loss from the QW is dominated by a nonradiative loss mechanism with an activation energy considerably smaller than that expected from direct thermal loss of electrons and holes into the barriers. We suggest that the improved device characteristics reported for lasers containing MQB's is due to effects other than the quantum interference of electrons     

Evaluation of multiquantum barriers in bulk double heterostructure visible laser diodes

Three bulk (Al/sub x/Ga/sub 1-x/)/sub 0.5/In/sub 0.5/P double heterostructure (DH) lasers were designed and fabricated to examine the effect of incorporating multiquantum barrier (MQB) structures. The first laser, used as a reference, has a conventional structure, while the remaining lasers include MQB structures, one designed to achieve a virtual barrier of 75 meV, the other having a transmission window up to 100 meV above the bulk barrier height. Measurements show a reduction of up to 31% in the room temperature threshold current and an increase in characteristic temperature of 20 K by the inclusion of the optimized MQB structure in comparison with the reference laser. However, since the leaky MQB design also shows a significant room temperature improvement over the reference laser we suggest that the device improvements produced by the MQB structures are not solely due to the formation of a virtual barrier.     

Temperature-dependent characteristics of 1.3-μm AlGaInAs-InPlasers with multiquantum barriers at the guiding layers

Strain-compensated 1.3-μm AlGaInAs-InP multiquantum-well (MQW) lasers with multiquantum barriers at both the n- and p-type guiding layers are comprehensively studied. The laser exhibits a characteristic temperature as high as 95 K and degradation in slope efficiency as low as -1.06 dB in the temperature range from 25°C to 75°C. The characteristic temperature of transparency current density is deduced to be 129 K. It is also found that the internal loss increases slowly with temperature, while the temperature dependence of the internal quantum efficiency dominates the degradation of the external quantum efficiency due to the degradation of the stimulated recombination, and significant increase of electron and hole leakage at high temperature     

InGaA1P超高亮度发光二极管

介绍了ＩｎＧａＡ１Ｐ超高亮度发光二级管的材料、器件、特性、结构及其应用。现已发展和生产坎德拉级的超高亮度投红色、黄色和绿色发光二极管。     

Temperature dependence of the threshold current for InGaAlP visiblelaser diodes

The temperature dependence of the threshold current for InGaAlP visible-light laser diodes was investigated from the standpoint of gain-current characteristics. The dependence of the light output power versus the current characteristic on the cavity length was evaluated for a 40-μm-wide InGaP-InGaAlP broad-stripe laser in the temperature range between -70 and 90°C. The threshold-current density dependence on the cavity length shows that a linear-gain approximation is suitable for this system. A minimum threshold-current density of 860 A/cm² was achieved at room temperature with a cavity length of 1160 μm. The internal quantum efficiency decreased in the temperature range higher than -10°C, which affected the excess threshold-current increase and the decrease in the characteristic temperature at this temperature range     

LP-MOCVD生长InGaAlP双异质结中In组分控制的研究

根据已经发表的有关文献实验数据 ,针对InGaAlP发光材料的LP -MOCVD生长 ,给出了描述In组分偏离的经验表达式 ,可应用于InGaAlP双异质结生长中In组分的控制     

A simplified model for graded-gap heterojunctions

A simplified method for calculating the energy band profiles of graded-gap heterojunctions, based on the generalized model of Oldham and Milnes, is presented. The profiles are derived by superposing an energy band grading function and the electrostatic potential in the heterojunction. The latter is obtained by using the depletion layer approximation as for conventional p-n homojunctions. The energy band profiles of hypothetical p(GaAs)-n(Al_0·4Ga_0·6As) heterojunctions are calculated using the simplified method. For small grading layer widths, the results are in good agreement with the generalized model. The barrier lowering factor η as a function of the graded layer width l is calculated for such heterojunctions. It is found, for acceptor and donor densities of 10¹⁸ and 10¹⁶ cm^?3 respectively, that the barrier height is reduced from 0·47 eV to zero as l increases from zero (abrupt case) to ≈300 Å. The applications of these analyses to practical heterojunctions are discussed.     

超高亮度InGaAlP590nmLED管芯设计

根据发光波长，化合物半导体能带隙和晶格常数三者的关系和实验数据，研究设计了ＩｎＧａＡｌＰ双异质结合各层的ｘ，ｙ值组成，掺杂浓度，厚度等整个ＬＥＤ的管芯结构，这种新颖的ＧａＰ（电流扩散层）／ＩｎＧａＡｌＰ（双异质结）／ＧａＰ（衬底）管芯结构，对５９０ｎｍ峰值波长全透明，比ＧａＰ或ＧａＡｌＡｓ（电流扩散层）／ＩｎＧａＡｌＰ（双异质结）／ＧａＡｓ（衬底）管芯结构的出光率高出两倍其外量子效率小于６％。     

Mg在InGaAlP及GaP材料中的掺杂行为

利用 SIMS分析技术 ,研究了在 In Ga Al P和 Ga P材料中 ,MOCVD工艺参数对 Mg的掺杂行为的影响 .实验结果表明 ,在较高温度下 ,Mg在生长表面的再蒸发决定了 Mg的掺杂浓度随衬底温度增加呈指数下降 ;而当载流子浓度饱和时 ,杂质 Mg在材料中的置换填隙机制使得 Mg的激活率随 Cp2 Mg流量的再增加反而下降 .同时通过计算得到 Mg在 In Ga Al P及 Ga P中的再蒸发激活能分别约为 0 .9e V和 1.1e V     

Mg在InGaAlP及GaP材料中的掺杂行为

利用SIMS分析技术,研究了在InGaAlP和GaP材料中,MOCVD工艺参数对Mg的掺杂行为的影响.实验结果表明,在较高温度下,Mg在生长表面的再蒸发决定了Mg的掺杂浓度随衬底温度增加呈指数下降;而当载流子浓度饱和时,杂质Mg在材料中的置换填隙机制使得Mg的激活率随Cp2Mg流量的再增加反而下降.同时通过计算得到Mg在InGaAlP及GaP中的再蒸发激活能分别约为0.9eV和1.1eV.     

Current injection in multiquantum well lasers

A model of current injection in a multiquantum well laser structure is proposed. A condition for uniform pumping of the wells is derived. For a given barrier height, uniform pumping can be achieved by increasing the ratio of the well-to-barrier thickness. The mechanism of current transport at thermal equilibrium for uniform pumping is by drift current in the barrier layers which equals the current injected from the external circuit.     

Strained InGaAsP multiquantum wells for optical electroabsorption waveguide modulators

The quantum-confined Stark effect in strained InGaAsP multiquantum wells with InGaAsP barriers and its application to the optical electroabsorption waveguide modulator are described. A large spectral red shift of more than 450 AA is observed at a low applied voltage of 3 V. An extinction ratio of >14 dB is demonstrated with a driving voltage as low as 5 V.<>     

InGaAlP LED发光特性分析

InGaAlP LED发光效率高，性能稳定，应用相当广泛。在InGaAlP LED的应用中，发光特性是相当重要的参数，而发光强度和半强度角是LED发光特性的两个主要参数。介绍了不同的InGaAlP LED芯片结构．分析了其发光特点及封装后的发光特性，讨论了不同的反射式支架结构对其发光特性产生的不同影响。     

Boundary conditions for pn heterojunctions

Boundary conditions for the excess minority carrier concentrations at the space-charge region (SCR) edges are developed and used to evaluate the current-voltage characteristics of pn heterojunctions. Carrier transport by drift and diffusion within the SCR, by thermionic emission across the interface, and by minority carrier diffusion within the quasi-neutral bulk are included. When transport across the interface is slower than that across the SCR, the results reduce to the emission-diffusion model of Perlman and Feucht. Alternatively, when carrier transport within the SCR is the limiting process, a result analogous to the diffusion theory of metal-semiconductor diodes results. Finally, if the current is limited by minority carrier diffusion within the quasi-neutral bulk, the quasi-Fermi levels are constant within the SCR and the results are similar to those for pn homojunctions.     

Three-dimensional analysis of multiquantum well DFB lasers

A three-dimensional analysis is presented by using the transfer-matrix method for 1.55 mu m InGaAs BH MQW DFB lasers. It is shown that the coupling coefficient becomes maximum and the threshold current density becomes minimum at a certain number of wells, depending on the stripe width.<>     

一种新型超高速多量子阱半导体激光器

报道了一种主要用作超高速光纤通信光时分复用(OTDM)系统的新型光源,即10GHz的被动外腔式锁模多量子阱半导体激光器,其具有脉冲宽度为2.9ps,波长调谐范围为1.53～1.57μm(40nm),输出光波长可精确稳定在1.55μm,锁模光脉冲的重复频率为10GHz,平均输出光功率为1mW及较小的时间抖动性(<0.6ps)等优点。     

InGaA1P超高亮LED性能及可靠性

InGaAlP超高亮LED是近年来发展的新型可见光LED,具有发光效率高,电流承受能力强及耐温性能好等特点,应用于各种户外显示与照明装置,本文汇集各厂家InGaAlP超高亮LED芯片,并制成器件,对其多种性能进行对比分析,测试超高亮LED的发光强度与电流的关系以研究饱和电流的大小,并进行电耐久性试验以考核超高亮LED芯片的可靠性,简要介绍了封装工艺设计对超高亮LED性能参数的影响,并提出了超高亮LED性能及可靠性的其它要求,为客户选用超高亮LED提供相对的依据。     

带有周期性微结构的InGaAlP量子阱发光二极管

在分析和研究圆盘型光学模式的基础上,本文提出并研制成功一种带有周期性环形沟槽结构的新型InGaAlP量子阱发光二极管.这种LED的制备工艺简单易行,效果明显.结果证实,与同样面积方形台面普通LED相比,这种LED的出光强度和效率都得到明显的增强和提高,为改进发光二极管的性能提供了一条新途径.     

LP-MOCVD生长InGaAlP外延层In组分控制的动力学分析

本文分析了低压转盘ＭＯＣＶＤ生长室中气流的流动特征,首次提出了在高温（７００℃左右）下生长ＩｎＧａＡｌＰ外延层时,抑制Ｉｎ组分脱吸附的“动压力模型”．解释了托盘转速和生长压力等生长参数对Ｉｎ组分控制的影响．     

Forward characteristics of heterojunctions

An empirical equation is put forward which describes the temperature-dependent behaviour of the forward characteristics of heterojunctions. No satisfactory theoretical derivation of this equation is yet available.