Growth and characteristics of optical single crystals for UV/VUV applications

Shimamura, Kiyoshi; Vı́llora, Encarnación G.

doi:10.1016/j.jfluchem.2011.06.044

Cited by 20 publications

(9 citation statements)

References 32 publications

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“…There is a continuous increase in research and applications of transparent semiconducting oxides (TSOs), such as In 2 O 3 , ZnO, SnO 2 and β‐Ga 2 O 3 whose bandgaps range from 2.7 to 4.8 eV. Unique properties of this class of materials make them suitable for electronic and optoelectronic applications, such as DUV photodetectors , photodiodes , transparent thin film transistors , light emitting diodes , Schottky diodes , high voltage MISFET and MESFET transistors , energy efficient windows , and also high temperature gas sensors . Bulk single crystals of all of these materials have already been demonstrated in sufficient size to prepare substrates for epitaxy.…”

Section: Introductionmentioning

confidence: 99%

“…Magnesium gallate, however, belongs to the group of “inverse” spinels where Mg 2+ occupies 50% of the positions that are normally occupied by the 3‐valent ion Ga 3+ . MgGa 2 O 4 should rather be described by the following formula: Ga[MgGa]O 4 [4,6]. The “degree of inversion”, x , may vary between x = 0 for a normal, and x = 1 for an inverse spinel.…”

Section: Introductionmentioning

confidence: 99%

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MgGa₂ O₄ as a new wide bandgap transparent semiconducting oxide: growth and properties of bulk single crystals

Galazka

Klimm

Irmscher

et al. 2015

Phys. Status Solidi A

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Bulk MgGa2O4 single crystals with inverse spinel structure were grown from the melt by different methods. The degree of inversion could be changed by suitable annealing, which was confirmed by differential scanning calorimetry analysis and corresponding changes of the specific heat capacity. MgGa2O4 is thermally much more stable at high temperatures than β‐Ga2O3 despite of a higher melting point of about 1930 °C and could be grown under a neutral atmosphere. Melt‐grown MgGa2O4 crystals were found to be either electrical insulators or n‐type semiconductors depending on the presence of oxygen in the growth atmosphere and the growth method applied. Growing the crystals in the presence of oxygen resulted in electrically insulating crystals. For as‐grown and intentionally undoped semiconducting crystals, the free electron concentration was in the range of 1017–1018 cm−3, but the electron mobility was relatively low, just a few cm2V−1s−1. The free electron concentration remained at a level of 1018 cm−3 after annealing in a hydrogen‐containing atmosphere at 600–900 °C for 10 h. On the other hand, annealing in an oxygen‐containing atmosphere above 600 °C for 10–40 h turns the crystals from the semiconducting to the insulating state. The optical bandgap at room temperature amounts to about 4.9 eV. It decreases with temperature at a rate of 1.35 meV/K. Cathodoluminescence spectra of as‐grown crystals show a dominant band at 362 nm. The melt‐grown crystals have sufficient size and structural quality to be used as substrates for epitaxy.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

MgGa₂ O₄ as a new wide bandgap transparent semiconducting oxide: growth and properties of bulk single crystals

Galazka

Klimm

Irmscher

et al. 2015

Phys. Status Solidi A

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“…Due to possibility of using high oxygen concentration in a growth chamber, the crucible-free OFZ method was successfully applied to growth b-Ga 2 O 3 single crystals from the melt [12,31,[35][36][37][38]40,84,85]. That method uses a sintered feed rod of Ga 2 O 3 with a seed rod located underneath.…”

Section: B-ga 2 Omentioning

confidence: 99%

Growth Measures to Achieve Bulk Single Crystals of Transparent Semiconducting and Conducting Oxides

Galazka

2015

Handbook of Crystal Growth

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“…Vacancy shows as a dioctahedral structure in the octahedron sheet. Normally, the tri-layer structure is linked together by K þ ion via weak ionic bonds [50][51][52][53]. For strong assemblage of adjacent layers, it is non-expandable.…”

Section: Introductionmentioning

confidence: 99%

Intensive study on structure transformation of muscovite single crystal under high-doseγ-ray irradiation and mechanism speculation

et al. 2019

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Intensive study on structure transformation of muscovite single crystal under high-dose γ -ray irradiation is essential for its use in irradiation detection and also beneficial for mechanism cognition on defect formation within a matrix of clay used in the disposal of high-level radioactive waste (HLRW). In this work, muscovite single crystal was irradiated with Co-60 γ ray in air at a dose rate of 54 Gy min −1 with doses of 0–1000 kGy. Then, structure transformation and mechanism were explored by Raman spectrum, Fourier-transform infrared spectrum, X-ray diffraction, thermogravimetric analysis, CA, scanning electron microscope and atomic force microscopy. The main results show that variations in the chemical/crystalline structure are dose-dependent. Low-dose irradiation sufficiently destroyed the structure, removing Si–OH, thus declining hydrophilicity. With dose increase up to 100 kGy, CA increased from 20° to 40°. Except for hydrophilicity variation, shrink occurred in the (004) lattice plane which later recovered; the variation range at 500 kGy irradiation was 0.5% close to 0.02 Å. The main mechanisms involved were framework break and H 2 O radiolysis. Framework break results in Si–OH removal and H 2 O radiolysis results in extra OH introduction. The extra introduced OH probably results in Si–OH bond regeneration, lattice plane shrink and recovered surface hydrophilicity. The importance of framework break and H 2 O radiolysis on structure transformation is dose-dependence. At low doses, framework break seems more important while at high doses H 2 O radiolysis is important. Generally, variations in the chemical structure and surface property are nonlinear and less at high doses. This indicates using the chemical structure or surface property variation to describe irradiation is correct at low doses but not at high doses. This finding is meaningful for realizing whether muscovite is suitable for detecting high-dose irradiation or not, and mechanism exploration is efficient for identifying the procedure for defect formation within the matrix of clay used in disposal HLRW in practice.

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Growth and characteristics of optical single crystals for UV/VUV applications

Cited by 20 publications

References 32 publications

MgGa₂ O₄ as a new wide bandgap transparent semiconducting oxide: growth and properties of bulk single crystals

MgGa₂ O₄ as a new wide bandgap transparent semiconducting oxide: growth and properties of bulk single crystals

Growth Measures to Achieve Bulk Single Crystals of Transparent Semiconducting and Conducting Oxides

Intensive study on structure transformation of muscovite single crystal under high-doseγ-ray irradiation and mechanism speculation

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Growth and characteristics of optical single crystals for UV/VUV applications

Cited by 20 publications

References 32 publications

MgGa2 O4 as a new wide bandgap transparent semiconducting oxide: growth and properties of bulk single crystals

MgGa2 O4 as a new wide bandgap transparent semiconducting oxide: growth and properties of bulk single crystals

Growth Measures to Achieve Bulk Single Crystals of Transparent Semiconducting and Conducting Oxides

Intensive study on structure transformation of muscovite single crystal under high-doseγ-ray irradiation and mechanism speculation

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Product

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MgGa₂ O₄ as a new wide bandgap transparent semiconducting oxide: growth and properties of bulk single crystals

MgGa₂ O₄ as a new wide bandgap transparent semiconducting oxide: growth and properties of bulk single crystals