Study of ion-beam-induced damage and luminescence properties in terbium-implanted AlGaN

Park, J.-H.*; Wakahara, Akihiro*; Okada, Hiroshi*; Furukawa, Yuzo*; Kim, Y.-T.*; Chang, H.-J.*; Song, J.*; Shin, S.*; Lee, J.-H.*; Sato, Shinichiro; et al.

Japanese Journal of Applied Physics, 49(3), p.032401_1 - 032401_5, 2010/03

https://doi.org/10.1143/JJAP.49.032401

380 keV proton irradiation effects on photoluminescence of Eu-doped GaN

Okada, Hiroshi*; Nakanishi, Yasuo*; Wakahara, Akihiro*; Yoshida, Akira*; Oshima, Takeshi

Nuclear Instruments and Methods in Physics Research B, 266(5), p.853 - 856, 2008/03

https://doi.org/10.1016/j.nimb.2007.12.103

To develop light emitting devices with radiation hardness, photoluminescence properties of non- and Eu-doped GaN after proton irradiation were investigated. The samples were irradiated with protons at 380 keV up to 110/cm at room temperature RT. The photoluminescence properties for the samples were measured at RT. As a results, the luminescence properties for non-doped GaN much decrease due to irradiation at 110/cm. On the other hand, for Eu-doped GaN, the luminescence properties that correspond to the transition did not show any degradation after irradiation at 110/cm.

Study of electron irradiation-induced defects in CuInSe and CuInGaSe by electron spin resonance

Okada, Hiroshi*; Lee, H.-S.*; Wakahara, Akihiro*; Yoshida, Akira*; Oshima, Takeshi; Kamiya, Tomihiro

Solar Energy Materials and Solar Cells, 90(1), p.93 - 99, 2006/01

https://doi.org/10.1016/j.solmat.2005.03.005

no abstracts in English

Improvement of luminescence capability of Tb-related emission by AlGaN

Nakanishi, Yasuo*; Wakahara, Akihiro*; Okada, Hiroshi*; Yoshida, Akira*; Oshima, Takeshi; Ito, Hisayoshi

Physica Status Solidi (B), 240(2), p.372 - 375, 2003/11

https://doi.org/10.1002/pssb.200303479

Luminescence propeties of Tb-doped AlGaN were studied. The samples were grown on sapphire substrates using OMVPE. Tb implantation was cariied out to introduce Tb into samples. After implantation, samples were annealed at 1000 to 1150 C in 10% NH diluted with N. The luminescence intensity for AlGaN x=0.1 is 5 times stronger than that for x=0 at 14 K. The luminesecence intensity for GaN rapidly decreases with temperature and its activation enegy is 7.8 meV. With increasing Al content, the activation enegy increases, and the activation energy for AlGaN is 70 meV.

Deep level transient spectroscopy study of electron-irradiated CuInSe thin films

Okada, Hiroshi*; Fujita, Naoki*; Lee, H.-S.*; Wakahara, Akihiro*; Yoshida, Akira*; Oshima, Takeshi; Ito, Hisayoshi

Journal of Electronic Materials, 32(9), p.L5 - L8, 2003/09

https://doi.org/10.1007/s11664-003-0234-8

no abstracts in English

Effects of Al composition on luminescence properties of europium implanted AlGaN(0x1)

Nakanishi, Yasuo*; Wakahara, Akihiro*; Okada, Hiroshi*; Yoshida, Akira*; Oshima, Takeshi; Ito, Hisayoshi; Shibata, Tomohiko*; Tanaka, Mitsuhiro*

Physica Status Solidi, 0(7), p.2623 - 2626, 2003/07

In our previous study, it was reported that Eu-doped Nitride semiconductors show luminescence propetires. In this study, we investigate the relationship between luminescence properties and Al composition using AlGaN(0x1). AlGaN were grown using OMVPE. Eu atoms were doped into the samples by ion implantation (200keV). After implantation, the samples were annealed to remove residual damege. Luminescence propreties of the samples were measured using photoluminescence and cathodeluminescence. As a result, luminescence at 621 nm which relates 4f-4f transition were observed for all samples (x=0 to 1). As for intensity, samples with x=0.5 show the strongest luminescence. This result can be interpreted in terms of the internal stress of crystals by the existence of Al atoms.

Effect of Cl ion implantation on electrical properties of CuInSe thin films

Tanaka, Toru*; Yamaguchi, Toshiyuki*; Oshima, Takeshi; Ito, Hisayoshi; Wakahara, Akihiro*; Yoshida, Akira*

Solar Energy Materials and Solar Cells, 75(1-2), p.109 - 113, 2003/01

https://doi.org/10.1016/S0927-0248(02)00115-0

Single crystalline CuInSe thin films grown on GaAs were implanted with Cl ions at room temperature. The mean concentration of Cl ranges from 5E17 to 5E19 /cm. Residual defects introduced in implantated layer are removed by annealing at 400C in N. As a result of Hall effects measuremant, electron concentration in implanted layer increases with increasing implanted Cl concentration. This result suggests that Cl acts as donor in CuLnSe. Ionizing energy of Cl is estimated to be 78 meV from the temperature dependence of electron concentation.

Effect of 3 MeV electron irradiation on the photoluminescence properties of Eu-doped GaN

Nakanishi, Yasuo*; Wakahara, Akihiro*; Okada, Hiroshi*; Yoshida, Akira*; Oshima, Takeshi; Ito, Hisayoshi

Applied Physics Letters, 81(11), p.1943 - 1945, 2002/09

https://doi.org/10.1063/1.1504873

Eu-doped GaN samples were irradiated with 3MeV-electrons at RT at 10 - 3x10/cm. Photoluminescence (PL) propeties related to D-F in Eu were studied using He-Cd laser as excitation source. As the results, it is found that PL intensity is not affected by electron irradiation.Considering that PL peak related to near-band-edge strongly decreases due to electron irradiation, we can conclude that PL related to D-F in Eu has very strong radiation resistance.

Photoluminescence properties of Eu-doped GaN by ion implantation

Nakanishi, Yasuo*; Wakahara, Akihiro*; Yoshida, Akira*; Oshima, Takeshi; Ito, Hisayoshi; Sakai, Shiro*

IPAP Conference Series 1 (Proceedings of International Workshop on Nitride Semiconductors), p.486 - 489, 2000/11

no abstracts in English

Electrical properties of radiation-damaged CuInSe thin films

Yoshida, Akira*; Natsume, Satoshi*; Lee, H.-S.*; Okada, Hiroshi*; Wakahara, Akihiro*; Oshima, Takeshi; Ito, Hisayoshi

no journal, , 

CuInSe (CIS)-based thin film solar cells have excellent radiation hardness and are promising in applications in space. However, although CIS thin film is used as an absorption layer in the cell, the details of radiation-induced degradation mechanism are not yet clear. In this report, n-type CIS thin film was fabricated by RF sputtering and was annealed at 823 K together with CuSe film evaporated on the CIS thin film, resulting in p-type CIS thin layer. The electrical properties of p-type CIS thin films were investigated. These films were irradiated with high energy electrons, up to the irradiation fluence 210[1/cm] of electrons accelerated up to 2 MeV. Over 110[1/cm], the resistivity began to increase drastically. The temperature dependence of the resistivity was measured below room temperature down to 20 K. These behaviors are explained by the grain-boundary-dominated transport with the increased barrier energy at the grain boundary.