Photoluminescence of Multilayer InAs Quantum Dots

采用MBE设备生长了多层InAs/GaAs量子点结构,测量了其变温光致发光谱和时间分辨光致发光谱。结果表明多层量子点结构有利于减小发光峰的半高宽,并且可以提高发光峰半高宽和发光寿命的温度稳定性。实验发现,加InGaAs盖层后,量子点发光峰的半高宽进一步减小,最小达到23.6 meV,并且发光峰出现红移。原因可能在于InGaAs盖层减小了InAs岛所受的应力,阻止了In组分的偏析,提高了InAs量子点尺寸分布的均匀性和质量,导致载流子在不同量子点中的迁移效应减弱。Multilayer InAs/GaAs quantum dots structures were grown by molecular-beam epitaxy(MBE).The steady-state and time-resolved photoluminescence of the samples were measured at various temperatures.Results showed that multilayer structures could not only narrow the photoluminescence FWHM(full width at the half maximum) but enhance the stability of the photoluminescence lifetime and FWHM.As for the quantum dots with InGaAs cap layer,the photoluminescent spectra became narrower(the narrowest FWHM was only 23.6meV) and the photoluminescent wavelength became longer.The possible reason for the above phenomena was that the InGaAs cap layer could both release the strains in InAs islands and inhibit segregation of In components,resulting in the weaker migration among different quantum dots

原子氢辅助分子束外延生长台阶状表面形貌的研究

研究了分子束外延中引入原子氢后，原子氢对外延层表面形貌特征形成的诱导作用，原子力显微镜（AFM），测试表明，在（311）AGaAs表面，原子氢导致了台阶状形貌的形成，在这种台阶状表面进一步生长了InAs量子点，测试结果表明其位置分布的有序化受到台阶高度和台阶周期的制约，这为实现量子点结构的有序化控制生长提供了一定的实验参考

Studies on Time-resolved Photoluminescence Spectrum of Wetting Layer and Quantum Dots in the Structure of Self-organized Quantum Dots

在GaAs(100)的衬底上,采用MBE自组织方法生长了单层层厚分别为2和2.5 ML,的InAs层。通过原子力显微镜(AFM)观察,证实已在InAs层中形成量子点.采用光致发光谱及时间分辨谱对InAs量子点及浸润层开展研究和对比,分析了单层InAs量子点和浸润层中的载流子迁移过程,较好地解释了实验结果.Single InAs layers (2 and 2.5 ML thick, respectively) were grown on (001) GaAs substrate by molecular-beam epitaxy (MBE). Formation of quantum dots was verified by atomic force microscopy (AFM). We studied and compared InAs quantum dots and wetting layer by photoluminescence and time-resolved spectrum. Migration of carriers among quantum dots and wetting layer were investigated, which explained our results well

自组织生长InAs量子点的发光性质研究

通过对加InGaAs自组织生长量子点的变温光致发光谱以及时间分辨谱的研究，发现低温下量子点的发光强度和光生载流子的寿命不变；中间温度区载流子寿命随温度升高而变大；更高温度时，发光强度和载流子寿命均随温度升高而快速下降

自组织生长单层InAs量子点结构中浸润层与量子点发光的时间分辨谱研究

在GaAs(100)的衬底上，采用MBE自组织方法生长了单层层厚分别为2和2．5ML的InAs层。通过原子力显微镜(AFM)观察，证实已在InAs层中形成量子点。采用光致发光谱及时间分辨谱对InAs量子点及浸润层开展研究和对比，分析了单层InAs量子点和浸润层中的载流子迁移过程，较好地解释了实验结果

Optical Properties of Self-organized InAs Quantum Dots

【中文文摘】通过对加InGaAs覆盖层的InAs自组织生长量子点的变温光致发光谱以及时间分辨谱的研究,发现低温下量子点的发光强度和光生载流子的寿命不变;中间温度区载流子寿命随温度升高而变大;更高温度时,发光强度和载流子寿命均随温度升高而快速下降. 【英文文摘】Optical properties of InAs/GaAs selforganized quantum dots(QDs) structures have been investigated by the temperaturedependent photoluminescence(PL) and timeresolved photoluminescence(TRPL) spectroscopies. It is found that the quantum dots have the intermediate behavior between the twodimensional and zerodimensional. That is, at low temperatures (<40 K), the PL intensities as well as the carrier lifetimes are independent of the temperature. At the middle temperature region (40～160 K), the carrier lifetimes quench quickly with the temperature.福建省自然科学重点基金(A992001)资

1.3微米发光自组织InAs/GaAs量子点的电致发光研究

用优化的MBE参数生长了1.3μm发光的InAs/GaAs量子点材料，并制成发光二极管，对不同温度和有源区长度下样品的电致发光谱进行了细致的研究。观察到两个明显的电致发光峰，分别对应于量子点基态和激发态的辐射复合发光。实验表明，由于能态填充效应的影响，适当增大量子点发光器件有源区长度，更有利于获得基态的光发射。这个结果提供了一种控制和调节InAs/GaAs量子点发光二极管和激光器的工作波长的方法

1.55μm波长发光的自组织InAs量子点生长

通过引入较长停顿时间，采用分子束外延循环生长方法在350℃低温获得了一种横向聚合的InAs自组织量子点，在荧光光谱中观察到1.55μm波长的发光峰。通过AFM和PL谱的联合研究，表明此低温循环生长方法有利于在长波长发光的量子点的形成

多层InAs量子点的光致发光研究

采用MBE设备生长了多层InAs／GaAs量子点结构，测量了其变温光致发光谱和时间分辨光致发光谱。结果表明多层量子点结构有利于减小发光峰的半高宽，并且可以提高发光峰半高宽和发光寿命的温度稳定性。实验发现，加InGaAs盖层后，量子点发光峰的半高宽进一步减小，最小达到23．6meV，并且发光峰出现红移。原因可能在于InGaAS盖层减小了InAs岛所受的应力，阻止了In组分的偏析，提高了InAs量子点尺寸分布的均匀性和质量，导致载流子在不同量子点中的迁移效应减弱