Photolwninescence experiments have been performed on GaAg-GaALAs,quantum well structures with well widths ranging from 40A to 145A.Both the intrinsic and extrinsic'transitions have been obserued.Relatively strong ...Photolwninescence experiments have been performed on GaAg-GaALAs,quantum well structures with well widths ranging from 40A to 145A.Both the intrinsic and extrinsic'transitions have been obserued.Relatively strong interface-related Luminescence is believed to be due to the presence of more trapped impurities at the inter-faces.展开更多
We have measured the time-resolved photoluminescence spectra of several In_(x)Ga_(1-x)As/GaAs single quantum well samples at 77K.The different temporal behaviors of the photoluminescence(PL)from the GaAs layer and the...We have measured the time-resolved photoluminescence spectra of several In_(x)Ga_(1-x)As/GaAs single quantum well samples at 77K.The different temporal behaviors of the photoluminescence(PL)from the GaAs layer and the excitonic emission from the In_(x)Ga_(1-x)As well were obtained.The lifetime for the exciton in the In_(x)Ga_(1-x)As well were determined to be 110-170ps.The trapping efficiency of the well to the carriers was about 80%.展开更多
A series of GaAs/InAs/GaAs samples were studied by double crystal X ray diffraction and the X ray dynamic theory was used to analyze the X ray diffraction results. As the thickness of InAs layer exceeds 1.7 monolayer,...A series of GaAs/InAs/GaAs samples were studied by double crystal X ray diffraction and the X ray dynamic theory was used to analyze the X ray diffraction results. As the thickness of InAs layer exceeds 1.7 monolayer, 3 dimensional InAs islands appear. Pendellosung fringes shifted. A multilayer structure model is proposed to describe the strain status in the InAs islands of the sample and a good agreement is obtained between the experimental and theoretical curves.展开更多
An unusual emission-I line has been observed in the photoluminescence spectra of MBE GaAs/AlAs MQW at 4.2K.Its half width is 6.5-9meV with peak energy Located between the near band transition and the free electrons to...An unusual emission-I line has been observed in the photoluminescence spectra of MBE GaAs/AlAs MQW at 4.2K.Its half width is 6.5-9meV with peak energy Located between the near band transition and the free electrons to carbon acceptors transition in bulk GaAs.The peak energy increases roughly linearly with the logarithm of the excitation power.The emission intensity decreases with the increase of temperature and disappears at about 15K.展开更多
Using photoreflectance(PR)at room temperature,we have studied GaAs/AlGaAs multi-quantum wells(MQWs)grown by molecular beam epitaxy.Analysis shows that the modulation mechanism of PR of MQWs is Stark shift of the subba...Using photoreflectance(PR)at room temperature,we have studied GaAs/AlGaAs multi-quantum wells(MQWs)grown by molecular beam epitaxy.Analysis shows that the modulation mechanism of PR of MQWs is Stark shift of the subbands produced by photo-injection of carriers,which has first derivative functional lineshapes.By fitting the experimental spectra,an unusual transition coming from the interfaces in MQWs was observed.展开更多
文摘Photolwninescence experiments have been performed on GaAg-GaALAs,quantum well structures with well widths ranging from 40A to 145A.Both the intrinsic and extrinsic'transitions have been obserued.Relatively strong interface-related Luminescence is believed to be due to the presence of more trapped impurities at the inter-faces.
文摘We have measured the time-resolved photoluminescence spectra of several In_(x)Ga_(1-x)As/GaAs single quantum well samples at 77K.The different temporal behaviors of the photoluminescence(PL)from the GaAs layer and the excitonic emission from the In_(x)Ga_(1-x)As well were obtained.The lifetime for the exciton in the In_(x)Ga_(1-x)As well were determined to be 110-170ps.The trapping efficiency of the well to the carriers was about 80%.
文摘A series of GaAs/InAs/GaAs samples were studied by double crystal X ray diffraction and the X ray dynamic theory was used to analyze the X ray diffraction results. As the thickness of InAs layer exceeds 1.7 monolayer, 3 dimensional InAs islands appear. Pendellosung fringes shifted. A multilayer structure model is proposed to describe the strain status in the InAs islands of the sample and a good agreement is obtained between the experimental and theoretical curves.
文摘An unusual emission-I line has been observed in the photoluminescence spectra of MBE GaAs/AlAs MQW at 4.2K.Its half width is 6.5-9meV with peak energy Located between the near band transition and the free electrons to carbon acceptors transition in bulk GaAs.The peak energy increases roughly linearly with the logarithm of the excitation power.The emission intensity decreases with the increase of temperature and disappears at about 15K.
文摘Using photoreflectance(PR)at room temperature,we have studied GaAs/AlGaAs multi-quantum wells(MQWs)grown by molecular beam epitaxy.Analysis shows that the modulation mechanism of PR of MQWs is Stark shift of the subbands produced by photo-injection of carriers,which has first derivative functional lineshapes.By fitting the experimental spectra,an unusual transition coming from the interfaces in MQWs was observed.
