Circular polarization from a nonmagnetic p-i-n resonant tunneling diode

The authors investigate the circular polarization of the electro- and photoluminescence emissions from the quantum well and contact layers of a nonmagnetic GaAs-AlAs p-i-n resonant tunneling diode under an external magnetic field. The contact emission evidences the formation of a spin polarized two-dimensional electron gas at the n-accumulation layer. The quantum well electroluminescence presents a strong sigma(-) degree of polarization, even for null Zeeman splitting energies, and a slight bias dependence. The observed circular polarization is mainly attributed to the spin polarization of the electrons injected into the quantum well from the two-dimensional electron gas. (c) 2007 American Institute of Physics.