Development of Near Infrared-Fluorescent Nanophosphors and Applications for Cancer Diagnosis and Therapy

The use of near infrared (NIR) light for biomedical photonics in the wavelength region between 800 and 2000 nm, which is called “biological window”, has received particular attention since water and biological tissues have minimal optical loss due to scattering and absorption as well as autofluorescence in this region. Recent development of InGaAs CCD enables observations in this wavelength region. In the present paper, we report development of Yb and Er-doped yttrium oxide nanoparticles (Y2O3:YbEr-NP) which show strong NIR emission under NIR excitation (NIR-NIR emission). We also demonstrate that NIR emission can be observed through swine colon wall. Based on these results, we propose a possible application of Y2O3:YbEr-NP for cancer diagnosis and therapy using NIR-NIR imaging system. Our results also suggest potential applications of Y2O3:YbEr-NP for noninvasive detection of various diseases

ジンブンガクブ キョウショク カテイ ウンエイ イインカイ 4ネンカン ノ トリクミ セイカ ト コンゴ ノ カダイ

本稿は、人文学部が完成年度を迎えた今年（平成29）度に、これまでの4年間の教職課程運営委員会の取組成果を明らかにし、今後の課題を明確にすることによって、学生の資質能力の一層の向上を図ることを目的としている。第1に本委員会の使命について述べ、第2に「師道塾」における実践的指導力の基礎の錬磨について考察した。（この項は、別稿において「論文」として投稿した。）第3に教育実習の参観指導について述べ、第4に「教職実践演習」による学生の質保証への取組とWEB入力上の諸問題を明らかにし、最後に、本委員会が着実な歩みを展開してきたことを示す資料として、平成27年度と平成29年度の「自己点検中間振り返り票」を事例として取り上げ、比較考察しながら、本委員会が達成できなかった事業を今後の課題として明らかにした

Surface Control Process of AlGaN for Suppression of Gate Leakage Currents in AlGaN/GaN Heterostructure Field Effect Transistors

We proposed a surface control process for suppressing the tunneling leakage of Schottky gates on AlGaN/GaN heterostructures. For the recovery of nitrogen-vacancy-related defects and reduction in the amount of oxygen impurities at the AlGaN surface, the process consisted of nitrogen radical treatment, the deposition of an ultrathin Al layer, UHV annealing and finally the removal of the Al layer. Ni/Au Schottky gates fabricated on processed AlGaN surfaces showed pronounced reduction in leakage current and a clear temperature dependence of I-V characteristics, indicating the effective suppression of tunneling leakage in current transport through AlGaN Schottky interfaces

Large reduction of leakage currents in AlGaN Schottky diodes by a surface control process and its mechanism

Leakage currents in AlGaN Schottky diodes were investigated systematically by using a rigorous computer simulation based on the thin surface barrier model taking account of unintentionally doped surface donors. The leakage currents in AlGaN Schottky diodes have stronger bias dependence and smaller temperature dependences as compared with those of GaN diodes. It was shown that these features were associated with shallow oxygen donors located near the AlGaN surface. Then, an attempt was made to remove oxygen and suppress leakage currents by a surface control process using an ultrathin Al layer and subsequent annealing. An in situ x-ray photoelectron spectroscopy analysis indicated the formation of Al2O3 layer during the surface control process, suggesting efficient gettering of oxygen from the surface. C-V analysis directly indicated the reduction of shallow donors by the surface control process. A remarkable reduction of reverse leakage currents of four to five orders of magnitude took place in large area AlGaN Schottky diodes after the application of the surface control process. This process also reduced leakage currents of the gate of the heterostructure field effect transistor device by more than one order of magnitude and increased temperature dependences of current. ©2006 American Vacuum Societ