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Spin-polarized excitons in pseudomorphic, strained In 0.16 Ga 0.84 </mml:mrow…

1992; American Physical Society; Volume: 45; Issue: 19 Linguagem: Inglês

10.1103/physrevb.45.11151

1095-3795

M. Kunzer, G. Hendorfer, U. Kaufmann, K. Köhler,

Electronic and Structural Properties of Oxides

Circularly polarized excitation light from a tunable Ti-doped sapphire laser has been used to produce spin-polarized excitons in strained, pseudomorphic ${\mathrm{In}}_{0.16}$${\mathrm{Ga}}_{0.84}$As/${\mathrm{Al}}_{0.29}$${\mathrm{Ga}}_{0.71}$As quantum wells (QW's) grown on GaAs substrates. By analyzing the degree of circular polarization of the exciton luminescence and by studying the depolarization effect of a transverse magnetic field, the optical lifetime and the spin-relaxation time of excited carriers can be determined in relatively wide wells. We further show that circular excitation offers a relatively simple means to discriminate unambiguously between light- and heavy-hole excitons. We have thus made measurements that yield optically determined band offsets for the QW system under investigation.