Mass Transfer in Closed Ampoule Vapor Crystal Growth

1981 ◽  
Vol 9 ◽  
Author(s):  
Franz Rosenberger

EXPANDED ABSTRACTClosed ampoule vapor transport techniques are widely employed for the preparation of single crystals [1–5]. The experimental simplicity of these techniques makes them also attractive for fundamental crystal growth transport studies in reduced gravity environments. However, the underlying transport processes are complex and difficult to quantify.

1993 ◽  
Vol 302 ◽  
Author(s):  
L. van den Berg

ABSTRACTA short review will be given of the methods by which mercuric iodide is prepared and purified to obtain material suitable for the growth of single crystals. The method used in our laboratory to grow single crystals up to 1,000 grams in weight from the vapor will be discussed. The effects of gravity on the growth process will be described.A crystal growth system suitable for operation in the reduced gravity environment of space was designed, and crystal growth experiments were performed during the flights of Spacelab 3 (April 1985) and the International Microgravity Laboratory (IML-1) (January 1992). The structural quality and electronic properties of the ground-based and spacegrown crystals were compared, and the results will be presented.


Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1562 ◽  
Author(s):  
Wen-Hao Chen ◽  
Zuo-Yan Qin ◽  
Xu-Yong Tian ◽  
Xu-Hui Zhong ◽  
Zhen-Hua Sun ◽  
...  

In this report, the development of physical vapor transport (PVT) methods for bulk aluminum nitride (AlN) crystal growth is reviewed. Three modified PVT methods with different features including selected growth at a conical zone, freestanding growth on a perforated sheet, and nucleation control with an inverse temperature gradient are discussed and compared in terms of the size and quality of the bulk AlN crystals they can produce as well as the process complexity. The PVT method with an inverse temperature gradient is able to significantly reduce the nucleation rate and realize the dominant growth of only one bulk AlN single crystal, and thus grow centimeter-sized bulk AlN single crystals. X-ray rocking curve (XRC) and Raman spectroscopy measurements showed a high crystalline quality of the prepared AlN crystals. The inverse temperature gradient provides an efficient and relatively low-cost method for the preparation of large-sized and high-quality AlN seed crystals used for seeded growth, devoted to the diameter enlargement and quality improvement of bulk AlN single crystals.


2020 ◽  
Vol 13 (12) ◽  
pp. 125503
Author(s):  
Atsushi Kotaki ◽  
Masao Yoshino ◽  
Yuui Yokota ◽  
Takashi Hanada ◽  
Akihiro Yamaji ◽  
...  

2014 ◽  
Author(s):  
Jeffrey J. Swab ◽  
James W. McCauley ◽  
Brady Butler ◽  
Daniel Snoha ◽  
Donovan Harris ◽  
...  

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 378
Author(s):  
Li Zhao ◽  
Zhiwei Hu ◽  
Hanjie Guo ◽  
Christoph Geibel ◽  
Hong-Ji Lin ◽  
...  

We report on the synthesis and physical properties of cm-sized CoGeO3 single crystals grown in a high pressure mirror furnace at pressures of 80 bar. Direction dependent magnetic susceptibility measurements on our single crystals reveal highly anisotropic magnetic properties that we attribute to the impact of strong single ion anisotropy appearing in this system with TN∼33.5 K. Furthermore, we observe effective magnetic moments that are exceeding the spin only values of the Co ions, which reveals the presence of sizable orbital moments in CoGeO3.


CrystEngComm ◽  
2021 ◽  
Author(s):  
Logan S Breton ◽  
Mark D. Smith ◽  
Hans-Conrad Zur Loye

Single crystals of new rubidium rare earth thiophosphates with the formulas Rb3Ln(PS4)2 (Ln = La, Pr, Ce), Rb3-xNaxLn(PS4)2 (Ln = Pr, Ce; x = 0.50, 0.55), and RbEuPS4 were crystallized...


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