Photoluminescence Characteristics of InAs Self-assembled Quantum Dots in InGaAs/GaAs Quantum Well

在InGaAs/GaAs量子阱中生长了两组InAs量子点样品,用扫描电子显微镜(SEM)测量发现,量子点呈棱状结构,而不是通常的金字塔结构,这是由多层结构的应力传递及InGaAs应变层的各向异性引起的。采用变温光致发光谱(TDPL)和时间分辨谱(TRPL)研究了其光致发光稳态和瞬态特性。研究发现,InGaAs量子阱层可以有效地缓冲InAs量子点中的应变,提高量子点的生长质量,可以在室温下探测到较强的发光峰。在量子阱中生长量子点可以获得室温下1 318 nm的发光,并且使其PL谱的半高宽减小到25 meV。Two types of InAs quantum dots grown in InGaAs/GaAs quantum well(DWELL) were fully investigated by time-resolved(TR) and temperature dependent photoluminescence(TDPL).Scanning electron microscopy(SEM) measurements show that the shape of quantum dots is prismatic,but not the common pyramid shape.We consider that it is attributed to stress transition of multi-layer structure and anisotropy of InGaAs strained layer.DWELL structures could combine both the effects of InGaAs buffer layer and cap layer and even effectively release the stress between the buffer layer and the QDs, which may greatly improve the QDs quality.Strong PL signal emitting at 1 318 nm can be detected at room temperature and the full width at half maximum of PL spectrum is only 25 meV at some temperature.浙江省舟山市科技项目(06110);; 浙江海洋学院人才引进项目(211050041

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

分子束外延InAs量子点材料的透射电子显微镜研究

报道了利用分子束外延技术在(001)GaAs衬底上生长的单层及多层InAs量子点材料的透射电子显微镜(TEM)研究结果，并对量子点的结构特性进行邓讨论。结果表

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