高激发功率对GaP∶N发光谱的影响

讨论了掺氮磷化镓（GaP∶N）荧光光谱的峰值强度（孤立氮等电子中心束缚激子发光峰A、最邻近N-N对束缚激子发光峰NN1和次邻近N-N对束缚激子发光峰NN3）随激发强度的变化规律,并在发光跃迁动力学方程中计入了由于高激发密度引起的样品温度升高,而导致孤立氮A的能级NA和最邻近N-N对NN1的能级的热激发的增强,得到了R（即最近邻N-N对(NN1)束缚激子发光峰与孤立N等电子中心束缚激子发光峰的强度比INN1/IA）与掺N浓度和激发光强的变化关系。利用实验数据进行拟合,得到了更好的拟合结果,并讨论了用此法计算GaP∶N样品中氮浓度时应注意的一些问题。     

高激发功率GaP：N发光谱的影响

讨论了掺氮磷化镓（GaP:N）荧光光谱的峰值强度（孤立氮等电子中心束缚激子发光峰A、最邻近N－N对束缚激子发光峰NH1和次邻近N－N对束缚激子发光峰NN3）随激发强度的变化规律,并在发光跃迁动力学方程中计入了由于高激发密度引起的样品温度升高,而导致孤立氮A的能级NA和最邻近N－N对NH1的能级的热激发的增强,得到了R（即最近N-N对（NH1）束缚激子发光峰与孤立N等电子中心束缚激子发光峰的强度比INN1／IA）与掺N浓度和激光发光强的变化关系。利用实验数据进行拟合,得到了更好的拟合结果,并讨论了用此法计算GaP:N样品中氮浓度时应注意的一些问题。     

掺施主和受主的GaP:N发光的热猝灭

对GaP:N(Te,Zn)中束缚激子发光热猝灭的测量和分析表明,中性Te原子以“俄歇阻断”作用,在NN对发光猝灭温度相对于不掺施主和受主的GaP:N有所降低方面起了关键的影响。掺Te后孤立N发光峰的猝灭温度提高,则是由于增加了N原子上电子分布的几率。这支持了N束缚激子的Hopfield-Thomas-Lyneh模型。受主Zn的作用是使自由激子发光随温度升高而缓慢增强,对A峰猝灭的减缓可能也有贡献。     

GaP:N(Te)中碲束缚激子发光的声子翼现象

在GaP:N(Te)的光致发光谱(PL)上,第一次发现了Te~0束缚激子发光伴生的声子翼,其中参与的声子是Dean曾经提出的D声子。对实验结果尚未有肯定的解释。另外,对掺杂GaP PL谱上熟知的双伴线,提出了有助于澄清问题的见解。     

高激发密度下磷化镓等电子陷阱束缚机制研究

一、前言 很早就有激子受激光发射的报导,激子激光器的研究越来越受到人们的重视,为此,在高激发强度下,研究磷化镓中等电子陷阱束缚激子发光,无疑具有重要意义。 多年来,人们对GaP中激子束缚机制进行了大量研究。HTL模型及Allen模型可以说是两个比较成功模型。前者注重于等电子杂质原子与所取代的基质原子在电负性上的差异,     

无序系统的次级光散射

本文试从无序系统的发光及喇曼散射中的几个问题出发,阐述次级光发射中的无序效应。Wolford研究了三元系GaAs_(1-x)P_x:N中束缚激子的发光,发现随着组份x值的变小,电-声子耦合增强,激子的半径变小。张新夷等人对三元系Ga_xIn_(1-x)P:N的束缚激子发光的研究也得到了同样的结论。在三元化合物中,束缚激子趋于局域,激子中电子和空穴的交换能增大。     

多声子尖峰叠加在连续钟形谱带上的发光光谱

<正> 虽然有几个作者已经研究了GaP:(Bi),AlxGa1-xP:(Bi)的发光光谱,但涉及光谱的谱形和谱线展宽的本质等问题还没引起注意和得到讨论。本文介绍这两个材料的光谱研究结果,并就上述问题展开讨论。     

GaP:N(Te)发光谱上的声子双伴线

根据GaP∶N(Te)的光致发光和喇曼光谱,提出了GaP∶N发光中的光学声子双伴线可能分别由LO~г和它的束缚态LO_(XN)~г对所产生的初步设想.另外,尝试对Te的声学声子翼中所含的组合声子作出判别.     

退火温度及气氛对Bi_4Ti_3O_(12)光致发光的影响

以Bi(NO3)3·5H2O和钛酸四丁酯[Ti(OC4H9)4]为原料,采用水热法制备了钛酸铋(Bi4Ti3O12,BiT)纳米材料。利用X线衍射(XRD)研究了产物的物相。结果表明,合成的产物为铋层状钙钛矿结构的BiT。N2气氛中不同退火温度下BiT纳米材料和BiT陶瓷的光致发光(PL)研究表明,420nm激发光激发下,470.6nm处的蓝-绿发光是因为氧空位捕获的电子和空穴形成的自束缚激子的辐射复合。而氧气氛中退火时发光强度减弱也表明蓝-绿发光与氧空位有关。     

Znse/GaAs超晶格的电子态和芯态激子

本文用半经验紧束缚法计算了ZnSe/GaAs(001)超晶格的能带结构,研究了其能隙与有效质量随层厚的变化.计算了(ZnSe)_5/(GaAs)_5超晶格中与杂质有关的芯态激子,其结果能说明相应异质结中束缚在Ga上的激子峰.本文还提出了该材料中导带底存在界面态.     

Luminescence decay kinetics in GaP:Bi and GaP:N

The lifetime of excitons bound to isoelectronic traps in GaP is studied as a function of temperature, excitation energy and intensity. The photoluminescence was excited both selectively and above the gap by using a pulsed, tunable dye laser with photon flux varying in the range of 10¹⁴–10¹⁹ photons/cm² per pulse. GaP:Bi shows a strong intensity dependence of τ(T) in the temperature range of 40–60 K due to the thermal activation of the electron. Similarly, GaP:N shows this behavior in the range of 20–100 K. In this case, two activation processes can be identified: release of the bound exciton into the free exciton band and dissociation of the exciton. The observed dependence of τ(T) on both excitation energy and intensity indicate that saturable deep traps (shunt paths) deplete the excess free carriers. These traps can be completely saturated in GaP:N while only partial saturation is achieved in GaP:Bi. The kinetic equations are written for GaP:Bi and solved numerically assuming quasiequilibrium conditions. Fitting this model to the experimental results yields the capture cross sections for carriers by Bi and by the deep traps as well as the concentration of the latter.     

用SiH_4-N_2进行PECVD生长高质量SiN研究

用ＳｉＨ４┐Ｎ２进行ＰＥＣＶＤ生长高质量ＳｉＮ研究刘英坤李明月（电子工业部第十三研究所，石家庄，０５００５１）１引言众所周知，氮化硅薄膜，尤其是低温等离子体淀积的氮化硅薄膜ＰＥＣＶＤ—ＳｉｘＮｙ，因其良好的物理化学性质和优越的制备工艺，在现代半导体器...     

非线性曲线拟合程序及其在半导体物理中的应用

本文论述了曲线拟合的数学模型及其用途与存在的困难。提出联合套用阻尼最小二乘法和复合形法可具有放宽初值要求、收敛速度快等优点。对拟合结果检验的必要性和方法作了讨论,给出非线性拟合的详细通用程序框图。应用本程序对硅太阳电池光谱响应、磷化镓发光二极管光电流谱,硅N-N~+-P结构光伏谱、磷化镓瞬态光电容谱、掺氮或掺铋磷化镓光致发光谱等半导体物理问题作了曲线拟合,并借助拟合结果分析完善了物理模型。     

Saturation behavior of extrinsic photoconductivity in GaP light emitting diodes at high infrared intensities

Saturation of extrinsic photoconductivity in GaP:N(Zn, Te) diodes could be achieved by excitation with a TEA-CO₂-laser. At wavelengths in the 10 μm range intensities of several 100 kW/cm² being near the damage threshold were applied. Carrier lifetimes of 60 ps at 4.2 K and 200 ps at 77 K could be estimated. The only conceivable mechanism explaining these short time constants is the capture of infrared excited holes by ionized shallow acceptors in the highly compensated p-side of the diode.     

Broadband near-infrared luminescence and energy transfer in Bi singly-doped and Bi/Yb co-doped titanate glasses

Super-broadband near-infrared(NIR)emission from 1100 nm to 1600 nm is observed in Bi-doped titanate glasses at the excitation of 808 nm laser diode(LD).The effects of Bi content on the optical spectra are investigated.It is also found that the Bi-related emission intensity can be enhanced by Yb3+co-doping at the excitation of 980 nm LD.It should be ascribed to the energy transfer from Yb3+to active Bi ions.The energy transfer processes are studied based on the Inokuti-Hirayama(I-H)model,and the energy transfer of electric dipole-dipole interaction is confirmed to be dominant in Bi/Yb co-doped glasses.     

Stimulated photoconductivity of copper-compensated gallium phosphide

The effect of the intrinsic excitation on the photoconductivity spectrum for the GaP:Cu samples is investigated. The specific features emerging as the additional peak at the photon energy ～1.8 eV are attributed to the effects of redistribution of nonequilibrium charge carriers generated from the first two energy levels of Cu in the surface potential field. The nature of the impurity photoconductivity band peaked at 1.05 eV with the edge at about 0.6 eV is discussed.     

Materials for light emitting diodes

III–V semiconductor display diodes fall into three material categories: direct, indirect, and diode-phosphor combinations. The light generation mechanisms are well understood in each case. On the basis of the luminous efficacy achieved in the laboratory, the merit of the various materials is in the order: GaP: N (green), GaP: Zn, O (red), GaInP (yellow), GaAsP (red), GaAlAs (red) and GaAs-phosphor combinations (red, green, blue). A more comprehensive assessment of quality must take into account factors such as the economic feasibility of the methods of synthesis, the applicability to monolithic arrays, and the suitability of spectra (hue, contrast, saturation, etc.). The degree of importance of these matters and the limitations of the various materials are less well-defined at present. New developments which may have an impact on the future of display diodes include the use of Al_xGa_1-xP in place of GaP to shift spectra to shorter wavelengths, the possible development of very bright direct alloys of InP with either GaP or A1P, and the doping of GaAsP with N to extend its range of colors.     

Evolution of Luminescence from Doped Gallium Phosphide over 40 Years

The results of luminescence studies conducted on the same samples of GaP over a 40-year period are discussed. The results strongly imply that periodic ordering of impurities improved the overall optical and mechanical properties of the material over time. Forty years after preparation, “hot” luminescence spectra in gallium phosphide (GaP) are similar to those for nanocrystals. The aged pure and N-doped crystals exhibit stimulated emission at 300 K. The aged GaP:N:Sm at room temperature generates bright green or yellow and red tunable luminescence. These results correlate with Raman light scattering and microhardness data obtained from the same crystals.