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An investigation on enhanced surface passivation in the existing industrial process line of large area n -type silicon (Si) Passivated Emitter Rear Totally diffused (n - PERT) solar cell has been performed. The Rapid Thermal Process (RTP) optimization for 20 min is conducted in the temperature range of 500–900°C and device evaluation is carried out with respect to regularly processed n -PERT solar cell. The impact of pre-metallization annealing is studied with the support of cell parameters like shunt resistance, reverse saturation current density determined from current-voltage measurements. The enhanced surface passivation via hydrogenation from silicon nitride (SiNx) layer during annealing is established with the help of external quantum efficiency, spectral response measurements and Fourier transform infrared spectroscopy analysis. The addition of optimized annealing resulted in improvement by 550% (from 38 to 247 µs), 7.73% (from 630.7 to 678.8 mV) and 84.77% (from 223.3 to 34 cm/s) in effective minority carrier lifetime, implied open circuit voltage and surface recombination velocity respectively. Finally, RTP technique for optimized process line has been successfully incorporated in industrial high-volume batch of 140898 CZ n-type Si wafers, which predicts conceptual validation of the study in mass scale production line with an increment in average efficiency of the device by 0.35%. [ABSTRACT FROM AUTHOR]

The ferroelectric and anisotropic electrical behaviors of barium magnesium fluoride (BaMg[F.sub.4]) single crystal grown under C[F.sub.4] atmosphere by the Czochralski method are analyzed by polarization hysteresis and impedance spectroscopy measurements. Dielectric polarization and ionic conductivity measurements at various temperatures and frequencies have disclosed quasi-one-dimensional ionic conduction phenomena along the c-axis and non-Debye dielectric relaxation along the axes.

Abstract: Growth of trivalent ions (La3+ and Nd3+) doped Bi4Ti3O12 (BIT) single crystal by self-flux method using excess Bi2O3 as flux is reported. The effects of trivalent ions on the structural, thermal, optical and ferroelectric properties of BIT crystal were investigated. The results of X-ray diffraction and thermal analysis, respectively, indicate that the lattice distortion, liquidus/crystallization temperatures of BIT considerably increase with La and Nd concentrations. Substitution of La in Bi3+ shifts the lower absorption edge towards the ultra-violet region (∼20–25nm), while no shift is observed for the BIT:Nd crystal. Regardless of the dopants, the optical microscopy patterns of the crystal surfaces reveal the existence of 90° domains. Dielectric measurements indicate that BIT:Nd crystals exhibit no significant variation in Curie temperature (T C) of BIT. Substitution of La and Nd in BIT increase both the remnant polarization (P r) and coercive field (E c) of BIT crystals. [Copyright &y& Elsevier]

Abstract: In this paper, we report the existence of anisotropic behavior along the crystallographic axes in optical, electrical and thermal properties of lithium tri borate, a recently developed vacuum UV-NLO material. The variation of refractive index with the wavelength along the crystallographic axes was investigated by prism coupling method. The results of impedance spectroscopy measurement reveal the presence of a strong anisotropy in ionic conductivity and dielectric constant along the axes and also show the super-ionic conduction behavior along the c-axis with the activation energy of Δ∼0.20eV. A thermo-mechanical study in the temperature range of 300–900K indicates the existence of a strong variation in the linear thermal expansion coefficient (positive value along the a-axis, and negative value along the c-axis) of LiB3O5 crystals. [Copyright &y& Elsevier]

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: Potassium niobate crystals were grown from high temperature solutions using the floating zone pulling-down technique. The starting solution compositions of K and Nb were changed from K:Nb=50:50 to 58:42. The lattice parameter, lattice volume and phase transformation temperature depended on the starting solution compositions. The solid solution region near the KNbO3 crystals was estimated to be expanding to a K-rich composition. [Copyright &y& Elsevier]