A novel way of modifying the thermal gradient in Vertical Bridgman‐Stockbarger Technique and studies on its effect on the growth of benzophenone single crystals

Abstract

In order to grow benzophenone single crystal, an organic nonlinear optical material, a cost-effective Vertical Bridgman-Stockbarger system has been designed and fabricated by employing a two-zone, transparent furnace made out of immiscible liquids. Transparent, optical quality benzophenone single crystals were successfully grown as a result of a suitable thermal gradient achieved by means of introducing an intermediate liquid in between the two immiscible liquids. The effect of change in the volume of the intermediate liquid thereby the thermal gradient on the growth parameters was analyzed. The quality of the grown single crystal was justified using X-ray powder diffraction analysis, FTIR, TG-DTA and optical transmission studies.

Numerical simulation of temperature field in the vertical Bridgman method crystal growth

“…T u =824,8249-0,26392 · z+0,0112 ·z 2 -1,13145· 10 -4 ·z 3 + 2,10979· 10 -7 ·z 4 (9) Where T p is the furnace temperature and T u is the temperature in the specimen.…”

“…For the given distance the temperature gradient in the furnace according to measured temperatures is 14.5C/cm. This value was used for calculation of subcooling in front of the boundary surface according to the equation (2) and in accordance with the work of Burden and Hunt 14:…”

Efficient growth techniques and properties of Benzophenone Single Crystals for NLO Applications:A Review

“…So from many literature surveys which had been discussed about various growth techniques such as indirect laser heated pedestal growth (ILHPG) method [15], MicrotubeCzochralski (μT-CZ) method [16], seed-oriented undercooled melt growth [17], Vertical Bridgman (VB) method [18], and uniaxially solution crystallization (USC) method of Sankaranarayanan-Ramasamy [19] have been reported with the aim of growing bulk organic NLO benzophenone single crystals. Among all the above stated methods, the Microtube-Czochralski and Vertical Bridgman methods are more versatile, bulk and unidirectional crystals can be grown by optimizing the growth parameters [12].…”

Direction Controlled Growth of Organic Single Crystals by Novel Growth Methods

“…In the literature, different kind of direction-controlled growth technique such as indirect laser heated pedestal growth (ILHPG) method [3], Microtube-Czochralski (µT-CZ) method [4], seed-oriented undercooled melt growth [5], Vertical Bridgman (VB) method [6], and uniaxially solution crystallization (USC) method of Sankaranarayanan-Ramasamy [7] have been reported with the aim of growing unidirectional NLO crystals. Despite the unidirectional organic NLO crystal can be grown by ILHPG [3] and seed-oriented undercooled melt growth [5], the complicated experimental set-up and multistep growth process leads to difficulty in growing large size unidirectional crystal.…”

“…Despite the unidirectional organic NLO crystal can be grown by ILHPG [3] and seed-oriented undercooled melt growth [5], the complicated experimental set-up and multistep growth process leads to difficulty in growing large size unidirectional crystal. Whereas the µT-CZ [4] and VB [6] methods are more versatile and bulk directional crystals can be grown by optimizing the growth parameters. On the other hand, the recently reported USC method [7] attracted the researchers by its unique advantage than the other methods such as unidirectional growth at ambient temperature which causes minimum thermal induced grown-in defects using simple experimental set-up with high solute-crystal conversion efficiency and high growth rate.…”