Laser Crystals

Kaminskii, Alexander A.

doi:10.1007/978-3-540-34838-2

Cited by 554 publications

(224 citation statements)

References 0 publications

Supporting

Mentioning

209

Contrasting

Unclassified

Order By: Relevance

“…For Eu 3ϩ ions in C 3V site symmetry only three crystal-field levels are predicted for the 5 D 0 → 7 F 2 transition. 15 The observation of more than three lines therefore suggests a local site symmetry lower than C 3V . An unambiguous assignment of the observed emission lines and Eu 3ϩ site symmetry, however, is not possible because of the existence of different Eu 3ϩ sites in GaN as will be discussed in the following.…”

Section: Form Approved Omb No 0704-0188mentioning

confidence: 91%

“…Characteristic intra-4 f Eu 3ϩ emission lines were observed in the visible spectral region and were assigned in accordance with previous reports of Eu 3ϩ ions in solid hosts. 14,15 The strongest Eu 3ϩ emission line peaked at 622.3 nm and was attributed to the transition 5 D 0 → 7 F 2 . The full width half maximum ͑FWHM͒ linewidth of the 622.3 nm emission was determined to be ϳ1.6 nm at 300 K. This linewidth is less than half of the value reported by Li et al 10 for GaN:Eu prepared by gas-source MBE on sapphire substrate, which indicates that the investigated sample is of higher crystalline quality and good uniformity.…”

Section: Form Approved Omb No 0704-0188mentioning

confidence: 99%

“…Moreover, it is possible that some emission lines arise from electron-phonon interactions and/or other impurities. 15 The PL decay transients under-above gap excitation monitored at ϳ622 nm at 14 and 300 K are shown in Fig. 1͑b͒.…”

Section: Form Approved Omb No 0704-0188mentioning

confidence: 99%

See 2 more Smart Citations

Spectral and time-resolved photoluminescence studies of Eu-doped GaN

Nyein

Hömmerich

Heikenfeld

et al. 2003

Applied Physics Letters

135

View full text Add to dashboard Cite

We report on spectral and time-resolved photoluminescence ͑PL͒ studies performed on Eu-doped GaN prepared by solid-source molecular-beam epitaxy. Using above-gap excitation, the integrated PL intensity of the main Eu 3ϩ line at 622.3 nm ( 5 D 0 → 7 F 2 transition͒ decreased by nearly 90% between 14 K and room temperature. Using below-gap excitation, the integrated intensity of this line decreased by only ϳ50% for the same temperature range. In addition, the Eu 3ϩ PL spectrum and decay dynamics changed significantly compared to above-gap excitation. These results suggest the existence of different Eu 3ϩ centers with distinct optical properties. Photoluminescence excitation measurements revealed resonant intra-4 f absorption lines of Eu 3ϩ ions, as well as a broad excitation band centered at ϳ400 nm. This broad excitation band overlaps higher lying intra-4 f Eu 3ϩ energy levels, providing an efficient pathway for carrier-mediated excitation of Eu 3ϩ ions in The visible and infrared light emissions from rare-earthdoped GaN ͑GaN:RE͒ are of significant current interest for applications in thin-film electroluminescence ͑EL͒ devices. [1][2][3][4] For achieving red light emission, the 5 D 0 → 7 F 2 intra-4 f transition of trivalent Eu 3ϩ ions seems most promising. Intense red photoluminescence ͑PL͒ around 622 nm from GaN:Eu ͑as-grown and ion-implanted͒ has been reported from several research groups. [1][2][3][4][5][6][7][8][9] In addition, several EL device structures based on GaN:Eu have been demonstrated. [1][2][3][4][5] The optimization of present EL devices, however, requires a more detailed understanding of the incorporation, excitation, and emission properties of Eu 3ϩ ions in the GaN host matrix.Several studies have recently appeared focusing on the preparation and optical properties of GaN:Eu. 4 -11 Based on the comparison to RE ions in other III-V semiconductors ͑e.g., InP:Yb, 12 GaAs:Er 13 ͒, the most probable lattice location for Eu 3ϩ ions in GaN are ͑substitutional͒ Ga sites, which have C 3V symmetry. However, significant differences in the Eu 3ϩ PL properties have been observed depending on the material preparation. Monteiro et al. 7 studied Euimplanted GaN and Eu in situ doped GaN grown by metalorganic chemical vapor deposition. They observed significant differences in the Eu 3ϩ PL properties, including the number of emission lines associated with the 5 D 0 → 7 F 2 transition. Based on optical spectroscopy and Rutherford backscattering studies, the authors concluded that the local symmetry of the Eu 3ϩ ions has to be lower than C 3V symmetry. 7 Bang et al. 9 studied Eu-doped GaN prepared by gas-source molecularbeam epitaxy ͑MBE͒ and concluded, based on extended x-ray absorption fine-structure data, that Eu 3ϩ occupies Ga sites with C 3V symmetry. It was also suggested that more than one local environment of Eu 3ϩ ions may exist in the investigated GaN samples.In this letter, we present PL results on GaN:Eu prepared by solid-source MBE, which provide spectroscopic evidence for the existence of different Eu...

show abstract

Section: Form Approved Omb No 0704-0188mentioning

confidence: 91%

Section: Form Approved Omb No 0704-0188mentioning

confidence: 99%

See 1 more Smart Citation

Spectral and time-resolved photoluminescence studies of Eu-doped GaN

Nyein

Hömmerich

Heikenfeld

et al. 2003

Applied Physics Letters

135

View full text Add to dashboard Cite

show abstract

“…The first excited manifold 6 P j of the Gd 3+ lies ϳ4.5 eV ͑318 nm͒ above the ground state 8 S 7/2 . 24 Since wurtzite AlN semiconductor material has a very large band gap, ϳ6.1 eV ͑203 nm͒, PL spectroscopy of this system requires deep UV sources. In the present experiments the quadrupled output from a Ti:sapphire laser led to aboveband-gap excitation of the AlN host.…”

mentioning

confidence: 99%

Ultraviolet photoluminescence from Gd-implanted AlN epilayers

Zavada

Nepal

Lin

et al. 2006

Applied Physics Letters

View full text Add to dashboard Cite

Deep ultraviolet emission from gadolinium ͑Gd͒-implanted AlN thin films has been observed using photoluminescence ͑PL͒ spectroscopy. The AlN epilayers were ion implanted with Gd to a total dose of ϳ6 ϫ 10 14 cm −2 . Using the output at 197 nm from a quadrupled Ti:sapphire laser, narrow PL emission was observed at 318 nm, characteristic of the trivalent Gd ion. A broader emission band, also centered at 318 nm, was measured with excitation at 263 nm. The PL emission intensity decreased by less than a factor of 3 over the sample temperature range of 10-300 K and decay transients were of the order of nanoseconds.

show abstract

“…) is a highly refractory material that has many practical applications, for example, it is used as sintering aids in the processing of ceramic materials and as a component for rare-earth (RE) doped lasers and optical windows [1]. In the last few years thin yttria films have attracted increasing attention.…”

mentioning

confidence: 99%

Oxygen-segregation-controlled epitaxy of Y2O3 films on Nb(110)

et al. 2000

View full text Add to dashboard Cite

Abstract. We demonstrate a very simple and reliable method of manufacturing clean, single-crystalline Y 2 O 3 films on Nb(110) substrates in situ. The method exploits the oxygen bulk contamination of Nb as a source of clean oxygen. For substrate temperatures above 800 K oxygen segregation to the Nb surface is so efficient, that yttrium becomes oxidized during deposition without any background oxygen pressure required in the ultrahigh vacuum system. The crystallinity and stoichiometry of these films can be tuned by the deposition temperature. For Y deposition at 1300 K the formation of well-ordered (111) ) is a highly refractory material that has many practical applications, for example, it is used as sintering aids in the processing of ceramic materials and as a component for rare-earth (RE) doped lasers and optical windows [1]. In the last few years thin yttria films have attracted increasing attention. Its high dielectric constant (ε = 13 − 17), its high resistivity, and high breakdown strength make Y 2 O 3 a viable candidate for silicon very-large-scale applications such as highdensity storage capacitors in miniaturized dynamic random access memory (DRAM) [2][3][4]. Moreover, Y 2 O 3 /Nb tunneling barriers were found among the best in interface quality and the highest in tunneling resistance and, consequently, meet important prerequisites for superconducting digital electronics [2]. It is obvious, that the unique properties of yttria depend critically on the presence of defects. Therefore, a simple and reliable method of manufacturing yttria films with controlled defect concentrations is desirable for both applications as well as for fundamental research on the electronic structure and bonding in crystalline yttria at the microscopic level. (110)-oriented Nb substrates. Their crystallinity and stoichiometry can be tuned by the deposition temperature. The crystalline quality of the films was examined by means of X-ray photoelectron diffraction (XPD) and low-energy electron diffraction (LEED). X-ray photoelectron spectroscopy (XPS) was used to study the chemical bonding in the yttrium oxide films. Film preparation and characterization were carried out in situ. Angle-resolved ultraviolet photoemission spectroscopy (ARUPS) results on the electronic structure of Y 2 O 3 films will be published elsewhere [6].XPD was chosen because of its chemical sensitivity and its sensitivity to local real-space order. It is a powerful technique for surface structural investigations [7], and it has been shown that full hemispherical XPD patterns provide very direct information about the near-surface structure [8]. At photoelectron kinetic energies above about 500 eV, the strongly anisotropic scattering of photoelectrons by the ion cores leads to a forward-focusing of the electron flux along the emitterscatterer axis. The photoelectron angular distribution, therefore, is to a first approximation a forward-projected image of the local structure around the photoemitters.

show abstract

Laser Crystals

Cited by 554 publications

References 0 publications

Spectral and time-resolved photoluminescence studies of Eu-doped GaN

Spectral and time-resolved photoluminescence studies of Eu-doped GaN

Ultraviolet photoluminescence from Gd-implanted AlN epilayers

Oxygen-segregation-controlled epitaxy of Y2O3 films on Nb(110)

Contact Info

Product

Resources

About