Dissertation Defense

Spin, Injection, Transport, and Modulation in III-V Semiconductors

Hyun Kum

Spintronic devices, which aim to utilize the quantum mechanical spin properties of electrons, offer the potential of high-speed and low-power operation with performance possibly exceeding those of conventional charge-based devices. Spin-based devices may also provide a route for the integration and simultaneous operation of both memory and logic elements. Ferromagnet/semiconductor heterojunction devices are favored over all-metal spintronic devices due to the long spin coherence time in semiconductors. Unfortunately, most spin devices studied today operate at cryogenic temperatures. For this technology to be successful, it is critical that the devices can be operated at or near room temperature in the absence of an externally applied magnetic field. It is also important to identify and characterize spin injectors with high injection efficiency at room temperature and semiconductors with low-dimensional quantum confined systems with long carrier spin coherence lifetimes.
In this thesis, we have investigated novel spintronic devices in the lateral and vertical geometry based on several III-V semiconducting materials (GaAs, InP, GaN). We demonstrate high temperature operation of these devices along with control and amplification of spin-based output signals via a third gate electrode.

Sponsored by

Pallab K. Bhattacharya