ISSN:
1089-7550
Quelle:
AIP Digital Archive
Thema:
Physik
Notizen:
By embedding piezoelectric InGaAs/GaAs multiple quantum wells (MQWs) in specifically designed p-i-n structures, we demonstrate that the nonlinear optical response can be used to identify the dominant screening mechanisms and simultaneously to determine the strain distribution. Furthermore, we show that a knowledge of the screening mechanisms and spatial band structure, in turn, can be used to control the nonlinear optical response. For this demonstration, we fabricate two p-i(MQW)-n samples on [111]-oriented GaAs substrates. The samples are designed such that, if the dominant screening is associated with photogenerated carriers that remain in the wells, a blue shift of the exciton would be expected in each. By contrast, if the screening is associated with carriers that have escaped the wells and moved to screen the entire MQW, one will shift to the blue and the other to the red if the lattice is mechanically clamped, but both will shift to the red if the lattice is mechanically free. The observation of a blue shift and a red shift indicates that, while in-well screening may be present, the dominant screening is out-of-well and that these particular structures are mechanically clamped to the lattice constant of the GaAs. Most importantly, these results illustrate the added flexibility that the piezoelectric field gives in tailoring the nonlinear optical response. © 1994 American Institute of Physics.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.357896
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