Research

1. Introduction
2. Spintronics
3. Control of spin current in 2DEG materials
4. Control of spin current in 2DEG oxide heterointerfaces
5. Organic and molecular spintronics
6. Hybrid solar cell
7. Atomic layer deposition




1. Introduction


The focus of our research group is the intersection of the fields of organic/molecular electronics, spintronics, optoelectronics with exploiting metal-organic hybrid materials. Within this umbrella we are pursuing projects involving both developing new hybrid materials with desired magnetic and electronic properties, electrical and optical studies of spin scattering, spin transport, and magnetic interactions in nanoscale hybrid structures, films from molecular monolayers to multi-layers, and novel hybrid hetero-structures.


2. Spintronics


Spintronics is an area of research that explores spin degree of freedom in electronic applications, which have been stimulated by the prospect of a new paradigm of electronics. The distinguishing and manipulating ‘spin’ as well as the charge properties of electrons add a new dimension to the conventional electronics. The perspective of spintronics has limitless concepts of novel solid-state electronic devices.



3. Control of spin current in 2DEG materials


2D materials, such as graphene, is a very promising spin channel material owing to the achievement of room-temperature spin transport with long spin diffusion lengths of several micrometres. Moreover, these materials have many interesting physical properties that also make it very attractive for spintronics, including gate-tunable carrier concentration and high electronic mobility. In the past decade, since the isolation of graphene, there have been many significant advances in exploiting spin currents in 2D materials, including efficient, defect-induced magnetism, theoretical understanding of the intrinsic and extrinsic spin?orbit coupling, and the investigation of the spin relaxation.




4. Control of spin current in 2DEG oxide heterointerfaces


Complex oxide have shown a number of exotic condensed matter phases, including high temperature superconductivity, multi-ferroics, etc. Recently, electron gas arisen at the insulating interfaces, such as LAO/STO have shown a variety of new and unusual electronic phases. Similar to materials made of 2D atomic sheets, the oxide heterointerface is a very promising spin channel material due to prospected long spin diffusion lengths, gate-tunable carrier concentration and high electronic mobility. With the progress of theoretical understanding for the intrinsic and extrinsic spin?orbit coupling, and the investigation of the spin diffusion in this materials should be exciting playground.





5. Organic and molecular spintronics


Organic spintronics is a hybrid of two hot fields: organic electronics and spintronics. With the possibility of creating unique molecular system from a bottom-up approach, the field opened up vast opportunities for discovering new fundamental phenomena. The ability to manipulate electron spin in organic molecular materials offers a new and extremely tantalizing route towards spin electronics, both from fundamental and technological points of view. This is mainly due to the unquestionable advantage of weak spin?orbit and hyperfine interactions in organic molecules, which leads to the possibility of preserving spin-coherence over times and distances much longer than in conventional metals or semiconductors.





6. Hybrid solar cell


Due to ever rising world’s demand for energy and uncertainties of future energy supplies, the research and development on next generation energy technologies become urgent tasks for our future economy and energy safety. No single solution can resolve these imminent challenges and investments on a variety of complemental approaches are necessary. The research and development of the organic electronics can also supplement essential necessities of future energy technologies.

Our group will focus on applying the atomic/molecular layer deposition method to control metal/organic interface and develop new hybrid materials for efficient absorption of light, dissociation of excitons, and improved charge transport. The application of the atomic/molecular layer deposition method will significantly improve fundamental understandings as well as technological advances in the organic/molecular electronic for the energy harvesting, storage, and usage.

Schematic view of the process of the organic photovoltaic effects




7. Atomic layer deposition


Tomorrow’s transistor, built atom by atom!

Careful investigation and development of the film growth is the central part for further development of organic/molecular electronics. Our group will primarily focus on the atomic/molecular layer deposition and their application mainly in the magneto- and opto-electronics.






In contrast to conventional methods of producing the organic films and the organic/metal molecular junctions, the atomic/molecular layer deposition will provide a high aspect ratio of a atomic/molecular level control with a conformal, pinhole-free layer and a clean metal/organic interface without metallic inter-diffusions.

The atomic layer deposition is similar in chemistry to the chemical vapor deposition (CVD) yet it exploits sequential surface controlled chemical reaction. In atomic layer deposition, the precursors are not mixed and are introduced into the reaction chamber pulse by pulse. By keeping the precursors separately and surface terminated chemical reaction, one can achieve atomic monolayer level control of film deposition. Due to surface controlled chemical reaction, the atomic layer coating will be very effective for high-aspect ratio coating of any nano-structured devices and maerials, such as nanoporous templates, nanotubes, nanofibers, and nanorod arrays. We will employ atomic layer deposition for the various functional coatings on nanostructures and developing plasmon-based photonic materials.

High-aspect ratio coating of ALD on various nanostructures