Executive Chief research Scientist, Research Institute for Electromagnetic Materials, Japan

Biography: Dr. Seishi Abe is executive chief research Scientist of Research Institute for Electromagnetic Materials (Tomiya, Japan). His current research is a physical preparation of composite thin films containing semiconductor nanocrystals and iron oxide thin films doped with metal elements. Dr. Abe earned his doctorate in materials science at Tohoku University (Sendai, Japan) in 1998 with the thesis “Preparation and Characterization of New Lead Chalcogenide Solid Solution Semiconductor for Mid-Infrared Laser”. Dr. Abe is currently an executive secretary of 3rd division (Electronics and Information Materials) in the technical committee and a member of the board of directors in Tohoku chapter of The Japan Institute of Metals and Materials.

Speech Title: Preparation of composite thin film with InSb and oxide semiconductor

Aims: Nanocomposite film with InSb nanocrystals dispersed in oxide semiconductor has potential application for quantum dot solar cells. In one-step synthesis of the nanocomposite, it is difficult to forecast how the composite will be formed, since the compound semiconductor, InSb, may be decomposed during the preparation process. In the present study, optimum composition is investigated to prepare a composite film with InSb nanocrystal dispersed in oxide semiconductor.

Methods: A composite film with InSb and oxide semiconductor was prepared by radio-frequency (RF) sputtering with a target of InSb chips set on oxide-semiconductor disk. In the present study, TiO2 and ZnO were employed as the oxide semiconductor. Film structure is observed using high resolution transmission electron spectroscopy (HRTEM).

Results: As-deposited film with InSb added oxide semiconductor forms amorphous structure. Hence, post-annealing is needed to crystallize the both. A composite film with InSb nanocrystals dispersed in oxide semiconductor is obtained at a restricted composition range. Optical absorption edge shifts due to a presence of InSb nanocrystals, which are clearly observed in a HRTEM image.

Conclusions: One-step synthesis of nanocomposite with InSb nanocrystals dispersed in oxide semiconductor is available using RF sputtering and subsequent heat-treatment.