Toward the ultimate electronic devices using abundant elements：Suemasu Laboratory скачать в хорошем качестве

Toward the ultimate electronic devices using abundant elements：Suemasu Laboratory

[Keio Spintronics Network - Suemasu Laboratory , University of Tsukuba] Toward the ultimate electronic devices using abundant elements Graduate School of Pure and Applied Sciences, University of Tsukuba (Electronics and Physics & Engineering) Takashi Suemasu Q.Regarding spin filter research, silicon integrated circuits are used in all kinds of devices, from everyday electrical appliances to supercomputers. A lot of research is being done to improve the performance of integrated circuits dramatically by using a property of electrons called spin. To improve the performance of devices, its very important to obtain electrons with their spin in either the up or the down state. There exist materials called half-metals, which have lots of spins in one state or the other. But the problem is that their crystal structures are complicated, so there are limitations on these materials. By contrast, were fabricating structures called resonance tunnel diodes. In principle, by using these devices, its possible to produce filters that can obtain electrons with one spin state, not only from ferromagnetic materials, but also from semiconductors. Q.Currently, about 95% of the electricity produced worldwide from solar cells comes from silicon. Because silicon is an abundant element in the Earths crust, and silicon technology is highly advanced, silicon is a very superior material. But during the last few years, the amount of silicon used has increased enormously. So people worldwide are researching how to make efficient solar cells using thin films. What were working on is a material called barium silicide. Its light-absorbing performance, as expressed by its light absorption coefficient, is about 100 times that of silicon. So with this material, solar cells can be made 100 times thinner. Our group has been confirming that a current actually flows when light shines on this material, and weve reached the stage where it can function as a solar cell. From now on, we aim to improve the efficiency of these solar cells a bit more. Q.We publish our results in many places, and at such times, people point out things that we hadnt noticed ourselves. For example, in the barium silicide solar cells were working on, crystal growth is aligned with the 111 plane of silicon. However, when we use a silicon substrate, we cant make thin-film solar cells. But someone told us that there exists technology for forming silicon films with 111 orientation on a glass substate. So we thought we could probably develop technology for forming such films on a glass substrate, and we shifted our approach to that direction. So its very interesting to publish our results, not only when the results are good, but also to receive lots of advice from different people.