| Recently, especially after the electron spin relaxation time of picosecond in quantum wells was measured at room temperature through exciton absorption bleaching, all-optical switching based on the electron spin relaxation in quantum wells has been the hotspot in recent research. Now most research concentrating optical switching is on GaAs MQW, while its working wavelength has been demonstrated around 850nm. On the other hand, InGaAsP MQW showed a faster spin relaxation time around 1550nm. So InGaAsP MQW has a more considerable application foreground in the field of all-optical switching. The main work is as follows:(1)The basic theory and status quo of all-optical switching on spin electronics are depicted, and the electron spin relaxation time and working wavelength are compared between GaAs and InGaAsP MQW.(2)The properties of exciton are depicted in weekly bound exciton model and two-dimensional exciton model, respectively. And the binding energy of heavy-hole exciton is calculated by the two-dimensional exciton model in InGaAsP MQW.(3)The ground energy of electron and heavy hole is calculated by the finite potential well model. Then the relations of composition and well width are calculated in lattice-matching and strain-compensation, respectively.(4) As spin relaxation depends on quantum well width, the spin relaxation time and excitonic absorption coefficient are calculated, through which the most congruent MQW structures for making all-optical switching based on spin relaxation are chosen from lattice-matching and strain-compensation structure respectively.(5)According to the calculation conclusion, two InGaAsP MQW are made and detected by X-ray diffraction and PL spectra, which proves they are according with theoretical calculation.
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