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In this letter, we demonstrate $1 \times 8$ linear metal–semiconductor–metal arrays of UV-C photodetectors based on optical-float-zone grown bulk (100)-oriented $\beta $ -Ga2O3. The as-grown polished bulk samples exhibited an RMS roughness of 1.4 nm and the full-width at half-maxima of 0.19°. The average peak responsivity (257 nm), dark current, photo-to-dark current ratio, and UV-to-visible rejection ratio of the devices in the array were measured to be 4 AW $^{-1}$ , 0.23 nA, $\sim 10^{2}$ , and $\sim 10^{3}$ , respectively, at a bias of 40 V. The uniformity as well as the variability of the detector parameters across the devices in the array was investigated before and after wire bonding. [ABSTRACT FROM AUTHOR]

Congruent LiNbO single crystals with Ti ion dopants (2 and 5 mol%) were successfully grown by Czochralski technique in the automatic diameter control facility. As-grown crystal boules were oriented into (0 0 1) direction cut and optically polished for all measurements. Influence of Ti-ion incorporation into LiNbO was studied by core level XPS analysis. Powder X-ray diffraction studies were carried out on doped lithium niobate for phase identification. High-resolution X-ray diffraction technique was used to study the crystalline quality through full-width at half-maximum values. The refractive index values are more for doped samples than for pure sample as determined by prism coupling technique with different laser sources. [ABSTRACT FROM AUTHOR]

Abstract: Beta barium borate (β-BaB2O4; BBO) single crystals have been grown from Na2O flux by the TSSG technique and the observed growth rate anisotropy is reported. The symmetrical conoscopic interference pattern on the c-cut plate confirmed strain-free and optical homogeneity of the crystals. The observed growth habits of as-grown crystals are explained using crystal growth theories. The relative growth rate along different crystallographic directions of BBO can be described by R [100] = R [010] > R [001]. The absorption measurements show a nearly 9nm shift in fundamental absorption edges in X and Z cut samples. Band gap energies measured were 6.45 and 6.2eV along the X and Z directions, respectively. The absorption spectra near the fundamental absorption edges (AE) follow Urbach’s rule. [Copyright &y& Elsevier]

Pure and Mn doped single domain near stoichiometric lithium niobate crystals have been grown by top seeded solution growth from 55 mol% Li solution. A uniform segregation of Mn throughout the crystal was obtained. Doping concentration decreases the Curie temperature while the absorption edge shift towards the longer wavelength region. Two color holographic recording was examined in Mn doped samples. Improved sensitivity, dynamic range and lifetime of the hologram for the doped crystal have been determined. The effect of Mn doping on the switching properties has been analyzed. [ABSTRACT FROM AUTHOR]

KTiOPO 4 single crystals doped with trivalent ion of Cr 3 + were grown by spontaneous nucleation and Top Seeded Solution Growth (TSSG) techniques. Two dimensional layer growth and striations were observed on the surfaces of doped crystals. Incorporation of Cr 3 + ions shifts the absorption edge towards the long-wavelength region. Dependence of refractive index with the incident photon energy for pure and doped crystals has been discussed. Incorporation of Cr ions decreases the ionic conductivity of pure KTP crystal by 1–2 orders of magnitude. In addition, shifting of relaxation peak was also observed in dielectric measurements. [ABSTRACT FROM AUTHOR]

Pure and MgO doped (up to 4 mol%) near-stoichiometric LiNbO 3 crystals are grown from Li rich (Li-55 mol%) melt. Significant improvement in the optical properties such as increase of optical damage resistance, accompanied by a shift in the –OH peak position in FTIR spectrum, and transparent range is observed at 1.75 mol% of MgO concentration in the crystal. Also the coercive field required for ferroelectric domain switching is minimum at 1.75 mol% MgO doping. Based on the results, the correlation between the defect structure and ferroelectric domain switching behavior in pure and MgO doped SLN is discussed. [ABSTRACT FROM AUTHOR]

Results of ionic conductivity and dielectric measurements on self-flux grown KTP crystals along b and c axes indicate the existence of super ionic conduction and one dimensional ionic conduction behaviors along the polar axis. SHG elements were fabricated for various thicknesses and their conversion efficiency has been discussed. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we report the growth of pure and Rhodium ion incorporated KTiOPO4 (Rh:KTP) single crystals by top seeded solution growth (TSSG) technique with an improved seeding procedure. The optical transmission/absorption spectra of pure and Rh:KTP crystals in the UV–VIS region are discussed. It is shown that the presence of Rh ion increases the indirect energy gap (E g) and shifts the lower absorption edge of KTP towards higher energy region. The ionic conductivity and dielectric properties of pure and Rh:KTP crystals were studied by means of impedance spectroscopy. The frequency and temperature dispersion behavior of dielectric constant and ionic conductivity of doped crystals are similar to pure KTP. Measured activation energies (E a) from the ionic conductivity and dielectric loss spectra indicate the existence of superionic conduction behavior. Linear thermal expansion coefficients of pure and doped crystals along the polar axis were obtained using a thermo mechanical analyzer. [Copyright &y& Elsevier]

KTiOPO4 single crystals doped with trivalent impurity ions of chromium were grown by spontaneous nucleation and seeded growth techniques. Structural refinement performed on the grown crystals by single crystal X-ray diffraction technique reveals that chromium ions occupy both the potassium sites with different filling coefficients. Incorporation of Cr3+ causes the absorption edge in the UV spectrum to shift towards the lower energy. The dependence of optical absorption coefficient with the incident photon energy in the UV–VIS region has been discussed. Optical and SEM studies indicate the existence of two-dimensional nucleation mechanisms. [Copyright &y& Elsevier]

Abstract: A thorough study reveals the importance of a proper synthesis condition in the growth of colour-free lead tungstate single crystals. An optimised synthesis scheme is described. The temperature gradient required, above the melt, for the growth of crack-free crystals is 25°C/cm. Differential thermal analysis shows that an improper synthesis results in a compositional variation along the vertical axis of the crystal. UV-visible absorption detects an enhanced absorption in the wavelength, 380–450nm for the pale yellow-coloured crystals. Annealing in air for 15h at 1050°C removes the special blue absorption in the coloured crystal. [Copyright &y& Elsevier]

Single crystals of lead zinc niobate-lead titanate (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 for x = 8% and 9% have been grown by flux method using Lead Oxide (PbO) as flux. Low scan rate XRD has been carried out to investigate on the structural influence of the compositional variations in the grown crystals. Transmission spectra in the range of UV-Vis-Near IR and mid IR regions have been carried out to understand the distortions caused in the BO6 octahedral lattice. Morphological aspects of as-grown PZN-PT crystals have also been investigated. Dielectric measurements clearly explained the dependence of Tc and diffusiveness with PT content. The values of Pr and Ecobtained from P-E loops suggest the presence of ordered domain state in these PZN-PT single crystals. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Abstract: Stability of the solution against spurious nucleation plays a dominant role in the growth of crystals at high growth rates requiring high levels of supersaturation. If any spurious nucleation does occur during a growth run, it becomes practically impossible to grow a very large crystal. A novel nucleation-trap crystallizer has been developed and used for the growth of crystals from aqueous solution so as to trap any unwanted nuclei and the particles that appear and settle at the bottom of the crystallizer during the growth process. In this crystallizer, any particles and nuclei nucleating during the growth are forced into the nucleation trap (or well) and subsequently by manipulating the temperature of the well; the growth of the nuclei is arrested. DKDP and ammonium acid phthalate crystals were grown in the developed system. X-ray rocking curve measurements on DKDP and ammonium acid phthalate crystals yielded FWHM of 89.1 and 29.71arcsec, respectively. [Copyright &y& Elsevier]