Semiconductor Nano-interfaces Group
A semiconductor device is made up of many interfaces, and the manufacturing process also corresponds to formation of individual interfaces, and both the function and the performance of the device depend on the manufacturing process. Our group aims to create semiconductor material systems either with new functions or with high performances by research and development of new processes of interface formation for mainly organic and IV group semiconductors. We also actively promote research and development in interdisciplinary fields that effectively utilize our developed material processing technologies.
(1) Research on charge carrier generation and charge transport at nano-interfaces between organic semiconductors
(2) Research and development of alignment control techniques of organic semiconducting molecules and high-performance functional organic devices
(3) Nano-structure formation process into Si semiconductor, doping process with using the burial nano-structure, Characterization of either burial or surface nano-structure and their electronic structures
(4) 2D arraying process of metal nanoparticles for plasmonics and its device applications
Si molecular beam epitaxy machine
Selected Recent Results
We demonstrated the improved PCE of BHJ OPVs fabricated by using the amorphous polymer (PEDOTNDIF) combined with neat and low-cost C70, compared with the BHJ OPV fabricated using PEDOTNDIF and PC70BM. The much-improved PCE is mainly due to a strong acceptor nature of neat C70, which needs to efficiently separate photo-excitons into free carriers. We also confirmed the good miscibility in the PEDOTNDIF:C70-based BHJ film. [Org. Electron. 25, 99 (2015)]
Highly oriented crystalline thin films of TIPS-pentacene, which is a promising organic semiconducting molecule, can be formed on solid substrates by flow-coating. The crystallographic a-axis is aligned parallel to the flow-coating direction. By flow-coating along the channel length direction of bottom-gate/bottom-contact-type organic field-effect transistors, we succeeded in reducing the device-to-device variation of the field-effect mobility to 6 %.
[Jpn. J. Appl. Phys. 53, 02BE01 (2014): Selected a spot lights article]
Development of SERS (surface enhanced Raman spectroscopy) substrate with usage of 2D array of metal nanoparticles for bio sensors. We succeeded in fabrication of SERS substrate with 2D array of Au=Ag (Please change "=" to "@") core shell nanoparticles having SERS enhancement factor of 107 with remarkable spatial uniformity [Chem. Phys. Lett. 605-606,115-120 (2014)].