New approaches to injection and detection spin polarized electrons into semiconductor structures

Objectives: The objectives of this research program are: 1) to obtain efficient spin injection into InAs at elevated temperatures by exploiting favorable structural, magnetic and electrical properties of ferromagnetic MnAs contacts grown in the zinc-blende structure on InAs-based materials; 2) to develop a usable all semiconductor spin injector by exploiting the Rashba effect in InAs and employing resonant tunneling from an InAs quantum well into an (InGa)As detector under a bias-created electric field; 3) to improve the efficiency and temperature robustness of spin injection from recently developed Fe/GaAs spin light emitting diodes (LEDs) which incorporate ultrathin InAs layers embedded in the GaAs Quantum wells. The approach is to measure the circular polarization of the electroluminescence emitted by these devices from which the injected electron spin polarization and therefore the device efficiency will be determined. Intellectual merit: There are considerable challenges in the design and growth of suitable structures for each of the projects to be undertaken. These challenges include the growth of the necessary structures, and understanding how the various growth parameters affect the outcome and how they can be controlled. Broader Impact : If this research is successful, it will have a significant impact on the field of spintronics, and thus possible future generations of information technology, by providing suitable efficient injection structures for both GaAs-based and InAs-based devices. An outreach program directed at high school students with the objective of providing them with exposure on the principles of wave-mechanics and its applications in nanostructures will be offered.