Improvement of Nd:GGG crystal growth process under dynamic atmosphere composition

In this paper, the temperature dependency of the required oxygen on the quality of Nd:GGG crystal during the growth process has been investigated. Based on the thermodynamic analysis, the oxygen partial pressure in the surrounding vapor phase should be as low as possible through heating the raw material at lower temperatures to prevent the oxidation of iridium to IrO2 (s). In order to eliminate the volatilization of Ga2O3, the oxygen was charged into the gas atmosphere (N2) near the Nd:GGG melting point. Powder X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) were employed to characterize the crystal quality under different growth atmosphere. The experimental results confirm the validity of thermodynamic calculations. It was predicted that charging the required oxygen at about 1950 K could reduce the iridium loss rate to about 36%. Consequently, it would be expected to acquire more favorable Nd:GGG crystals with quite improved properties by applying the accurate growth conditions.

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