ECCS-0754367 P. Bhattacharya, University of Michigan Ann Arbor
Objective: The objective of this research is to realize high-temperature (>200K) spintronic devices with InP-based hetrostructures grown by molecular beam epitaxy. The reasons of choosing InP-based hetrostructures are the following : (i) these are used for high frequency transistors and for fiber-optic communication at 1.3 and 1.55 µm; even for future CMOS-based VLSI, InAs and InSb on silicon are being investigated for the superior carrier transport properties therein; (ii) very little is experimentally known regarding spin injection in InP-based alloys. The approach is to investigate and realize three specific devices: (a) spin valves for the study of spin injection, transport and detection; (b) semiconductor-ferromagnet based memory devices; and (c) spin lasers and their modulation with spin torque devices.
Intellectual Merit: Spin-based ferromagnet/semiconductor heterojunction devices are particularly attractive, compared to all-metal spintronic devices, due to the versatility and the long spin coherence time in semiconductors. However, till date, practical semiconductor spintronic devices that can operate at or near room temperature do not exist. The proposed program of research will address this critical need.
Broader Impact: The proposed program is interdisciplinary in nature and will provide a broad impact to science and society beyond technical merits. The economic impact of the research and its outcome will be felt as the proposed devices complement or selectively replace traditional microelectronics. This work combines spintronics with other fields in science and engineering for real applications. Outreach projects for women and underrepresented minorities are proposed to provide research experience for undergraduates and expose high school students to scientific and engineering disciplines.
NSF Project Outcomes for the General Public for Award ID 0754367 Moore’s law, which states that the number of transistors in a computer doubles every year, will hit a fundamental barrier, both in terms of processing and fundamental physics, that will preclude chipmakers from increasing the performance and efficiency of computer microchips in the coming years. The International Technology Roadmap for Semiconductors (ITRS) has identified the electron’s spin angular momentum as a potential technology to usher in a new paradigm in computer logic and storage that could continue the trend of increasing the performance of microchips each year. These "spintronic" devices rely on utilizing the spin degree of freedom of electrons rather than their charge, resulting in much reduced power dissipation and faster logic calculations that will outperform current charge based gadgets such as personal computers and cell phones. We have characterized potential spintronic materials and devices on various kinds of substrates and have achieved room temperature operation of spintronic transistors, memory elements, and lasers. Spin lasers are very useful in studying various biological materials such as proteins, as well as secure communication through quantum cryptography. Spin transistors can be used as logic or memory element in a computer. A key feature of these products is that they are readily integratable with current technology such that a radical change in fabrication techniques or packaging, which could cost up to billions of dollars to re-implement, is not required.
