Model calculation and experimental data of circularly-polarized-light-dependent photocurrent in a n-GaAlAs/p-GaInAs/ p-GaAs heterostructure are reported. It is found that, with appropriate heterojunction parameters, spin voltaic effect may survive across the heterojunction and give rise to detectable polarization-dependent photocurrent signals which are greater than those due to the magnetic-circular-dichroism background.

The physical properties of the III-N-based quaternary magnetic alloy semiconductor (Ga,In,Mn)N prepared by RF-plasma-assisted molecular beam epitaxy are reported. Epilayers are either highly resistive or n-type, and exhibit paramagnetic behavior. Magnetic circular dichroism (MCD) spectra show the presence of spin-polarized band-to-band transition (3–3.5 eV), the Mn2+ d-d * intra-ionic transition (∼2.3 eV), and the transition associated with rather deep Mn acceptor level (∼1.7 eV). Green-emission band (∼2.3 eV) is observed in photoluminescence experiments for In-containing samples. Near-band-edge emission (∼3.4 eV) is also obtained from multiple-quantum-well structures. n-type samples show negative magnetoresistance at RT, from which strong s,p-d spin exchange interaction is inferred.

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Theoretical and experimental examinations of spin transport across the p-n heterojunction are described. The analytical consideration reveals that the SVE is feasible when the appropriate heterostructure parameters are chosen, even if thermionic emission takes place across the heterojunction. Experimental data obtained from n-(Al,Ga)As/p-(In,Ga)As heterojunction diodes show that, under the forward bias condition, the circularly-polarized-light-dependent photocurrent component exhibits characteristic magnetic field dependence, which suggests the contribution of SVE.