- 著者
- Baba Masakazu Tsurekawa Sadahiro Watanabe Kentaro Du W. Toko Kaoru Hara Kosuke O. Usami Noritaka Sekiguchi Takashi Suemasu Takashi
- 出版者
- American Institute of Physics
- 雑誌
- Applied physics letters (ISSN:00036951)
- 巻号頁・発行日
- vol.103, no.14, pp.142113, 2013-09
- 被引用文献数
- 29 3
Potential variations around the grain boundaries (GBs) on the surface in undoped n-BaSi2 epitaxial films on Si(111) and Si(001) were analyzed using Kelvin prove force microcopy. The potentials were higher at GBs than those in the BaSi2 grains on Si(111). The average barrier height was approximately 30 meV at the GBs, indicating that the enhanced potentials repulse photogenerated holes so that the charge carrier recombination can be effectively reduced. In contrast, the potentials were smaller at GBs in the BaSi2 on Si(001), and the average barrier heights were approximately 30 and 50 meV along Si[1–10] and [110], respectively.
- 著者
- Chen Shaoqiang Dierre Benjamin Lee Woong Sekiguchi Takashi Tomita Shigeo Kudo Hiroshi Akimoto Katsuhiro
- 出版者
- American Institute of Physics
- 雑誌
- Applied physics letters (ISSN:00036951)
- 巻号頁・発行日
- vol.96, no.18, pp.181901, 2010
- 被引用文献数
- 32 12
Erbium-doped GaN with different doping concentrations were grown by ammonia-source molecular beam epitaxy. The intra-4f-shell transitions related green luminescence were observed by both photoluminescence (PL) and cathodoluminescence (CL) measurements. It was found that concentration quenching of Er-related luminescence was observed in PL measurements while not in CL measurements. The different excitation and relaxation processes are suggested as the cause of the concentration quenching characteristics between PL and CL. The strong Er-related CL intensity in highly doped GaN demonstrates that high energy excitation is a promising approach to suppress the concentration quenching in Er-doped GaN.
- 著者
- Ootsuka Teruhisa Suemasu Takashi Chen Jun Sekiguchi Takashi Hara Yoshiaki
- 出版者
- American Institute of Physics
- 雑誌
- Applied physics letters (ISSN:00036951)
- 巻号頁・発行日
- vol.92, no.19, pp.192114, 2008-05
- 被引用文献数
- 14
We have evaluated the lifetime and diffusion length of photogenerated minority carriers (holes) in single-crystalline n-type beta-FeSi2 bulk grown by chemical vapor transport. The diffusion length measured by optical-beam-induced current agreed well with that measured by electron-beam-induced current, that is, 51 and 38 µm, respectively, for samples annealed at 800 °C for 8 h. The decay curve of photoconductivity obtained by 1.31 and 1.55 µm light pulses was well fitted by assuming a carrier lifetime of approximately a few microseconds. The mobility of photogenerated minority carriers was estimated to be approximately 200–360 cm2/V s from the measured lifetime and diffusion length.
- 著者
- Ootsuka Teruhisa Suemasu Takashi Chen Jun Sekiguchi Takashi
- 出版者
- American Institute of Physics
- 雑誌
- APPLIED PHYSICS LETTERS (ISSN:00036951)
- 巻号頁・発行日
- vol.92, no.4, pp.042117, 2008-01
- 被引用文献数
- 13 15
We have evaluated the diffusion length of minority carriers (holes) in single-crystalline n-type beta-FeSi2 bulk grown by chemical vapor transport by means of electron-beam-induced current (EBIC) technique in the edge-scan configuration. The EBIC line-scan data showed a clear exponential dependence of distance from the Al electrode. The diffusion length was estimated to be 20 µm at room temperature, and increased upon high-temperature annealing, reaching approximately 30 µm after annealing at 800 °C for 8 h. This result explained the improvement of photoresponsivity in the Al/n-beta-FeSi2 Schottky diodes by high-temperature annealing.