Abstract

Spin, the magnetic moment of electrons, began to receive considerable attention from the microelectronics industry with the appearance of Giant Magneto-Resistance (GMR) devices more than 15 years ago. This initial success led to the concept of spin electronics or “spintronics”. Although GMR and related devices are all-metal, much progress in extending these successes to semiconductors has recently been made. Work on semiconductor spin injection, transport and detection will possibly bring a bright future for technology, providing efficiency and high speed to semiconductor devices by providing a new paradigm for information processing to surmount existing intractable difficulties. Among various interesting spintronic devices, the hot electron spin valve device (where electrons carrying information have energy much higher than the Fermi energy) provides a unique way to explore the spin world in semiconductor devices.

This research mainly investigates the optical hot electron spin valve effect in spintronic devices. Instead of utilizing a Schottky barrier or tunnel junction to generate hot electrons electrically, the devices investigated in this thesis use inelastic photon scattering to explore hot electron generation and transport in a ferromagnetic metal/semiconductor spin valve device.

The outline of this thesis will be as follows: First, the background of this research will be introduced. Then, photo-excited hot electron spin valve effects are investigated using our devices, the Spin Valve Photo-Diode and the Spin Valve Photo-Transistor; fabrication and measurement are both described in detail. Finally, possible future experiments and applications based on this work are discussed.