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
Photor&fleatanae of GaAs doping superlattices has been measured at 300K.The spectra exhibi,te features cowesponding to spatially direct transitions due to quantized electron or hole states.We demonstrate the utili...Photor&fleatanae of GaAs doping superlattices has been measured at 300K.The spectra exhibi,te features cowesponding to spatially direct transitions due to quantized electron or hole states.We demonstrate the utility of the photoreflectance technique for studying quantum size effects tn doping superlattices.展开更多
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
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.
文摘Photor&fleatanae of GaAs doping superlattices has been measured at 300K.The spectra exhibi,te features cowesponding to spatially direct transitions due to quantized electron or hole states.We demonstrate the utility of the photoreflectance technique for studying quantum size effects tn doping superlattices.
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.
