Application of the accelerated crucible rotation technique to the Bridgman growth of CdxHg1− xTe: Simulations and crystal growth

Growth of Hg1−xCdxTe single crystals by travelling heater method under accelerated crucible rotation conditions

“…However, calculations by Gray et al [15] have suggested, that hypothetic striations in Hg t _xCdxTe would rapidly decay by solid-state diffusion because of the high self-diffusion coefficient (D = 4.41 × 10 -t~ cm 2 s -~ at 500°C, x = 0.21 [16]). This is in agreement with the ACRT Bridgman growth experiments [10,12], which have used a growth rate of 0.5 mm h-~ and an ACRT sequence of spin-up for 8 s and spin-down of 1 s. The authors did not observe striations. In our experiments, if striations occur, the spacing from ACRT would lie in the same range, and should not be stable.…”

“…This means that a macroscopically smooth interface changes to a cellular substructure if the actual temperature at some point in front of the interface becomes lower than the equilibrium temperature of the actual concentration of the species in the solvent at just this position. Other authors dealing with crystal growth with ACRT [6][7][8][9][10][11][12] have not given any basic explanation for the reasons why forced convection can increase the maximum growth rate limit. This will be attempted in the following paragraph.…”

“…This technique was first used by Scheel [6] to grow crystals of garnets from high-temperature solutions. Further studies have been on the application of ACRT to THM growth of CdTe crystals [7] and to Bridgman growth of Hg t _xCdxTe alloys [8][9][10][11][12]. Whereas there has been a patent on this subject [13], this is the first report in the open literature on the THM crystal growth of Hg i_,Cd,Te using ACRT.…”

Simulating Interface Growth and Defect Generation in CZT – Simulation State of the Art and Known Gaps

“…Accelerated crucible rotation technique (ACRT) [16,17,[77][78][79][80] has been used in crystal growth for many years; the purpose of acceleration being to maximize convective flow by generating Ekman boundary layers at solid surfaces [81]. A series of experimental studies of ACRT has been conducted by Caper and coworkers [77][78][79][80], and they observed Ekman flow and a sidewall instability, which is identified as a Couette instability.…”

“…A series of experimental studies of ACRT has been conducted by Caper and coworkers [77][78][79][80], and they observed Ekman flow and a sidewall instability, which is identified as a Couette instability. A. Yeckel and J. J. Derby [54] used continuum crystal growth models to numerically simulated the ACRT applied to the vertical solidification system, and sidewall instability was shown in their results and identified as a Taylor-Görtler boundary layer instability [82].…”