Abstract

The process of the development of the nuclei and of subsequent seeding in "contactless" physical vapor transport is investigated experimentally. Consecutive stages of low supersaturation nucleation in the "contactless" geometry for the growth of CdTe crystals from the vapor are shown. The effects of the temperature field, geometry of the system, and the experimental procedures on the process are presented and discussed. The experimental results are found to be consistent with our earlier numerical modeling results.

Author Keywords: Theory and models of crystal growth; Growth from the vapor

PACS classification codes: 81.10.Aj; 81.10.Bk; 81.20.-n

Article Outline

1. Introduction

2. Experimental system and procedure

3. Results and discussion

3.1. Optimum LSN conditions

3.2. The effect of the shape of the furnace temperature profile

3.3. The effect of the temperature and pulling rate

3.4. The effect of the initial position of the ampoule

3.5. The effect of the amount of the source material

4. Comparison with theoretical calculations and modeling

5. Summary

Acknowledgements

References

(40K)
Fig. 1. Five consecutive stages of the optimum low supersaturation nucleation process: (a) the source material is compacted at the bottom of the ampoule, position of the pedestal in the furnace z_p=6 mm, (b) z_p=9.5 mm, the top surface of the source material is reshaped into a cone, (c) z_p=10 mm, the tip of the cone is adhered to the crystal holder, (d) z_p=14 mm, the nucleus is spread out onto the face of the crystal holder, (e) z_p=16 mm, the nucleus is detached from the source material.

(28K)
Fig. 2. The dependence of the shape of the source material on the temperature gradient in the furnace. (a)–(d) shapes of the source cones for temperature profiles A–D, respectively; (e) temperature profiles of the furnace.

(35K)
Fig. 3. Source material cones formed under different temperature and translation conditions. (a) the temperature profiles used; (b) pulling rate 0.7 mm/h, temperature profile C; (c) 0.7 mm/h, temperature profile E; (d) 0.7 mm/h, temperature profile F; (e) 1.4 mm/h, temperature profile C.

(37K)
Fig. 4. The effect of the ampoule initial position on the state of the process at the late stage of the cone formation (z_p=12 mm). (a) optimum, (b) and (c) 3 and 6 mm above the optimum starting position, respectively.

(35K)
Fig. 5. The effect of the amount of the source material: (a) 90%; (b) 100%; (c) 110% of the optimum amount.

References

1. K. Grasza, S.B. Trivedi, Zengchen Yu, S.W. Kutcher, W. Palosz and G.A. Brost. J. Crystal Growth 174 (1997), p. 719. SummaryPlus | Full Text + Links | PDF (457 K)

2. K. Grasza, U. Zuzga-Grasza, A. Jedrzejczak, R.R. Galazka, J. Majewski, A. Szadkowski and E. Grodzicka. J. Crystal Growth 123 (1992), p. 519. Abstract

3. K. Grasza. J. Crystal Growth 146 (1995), p. 65. Abstract | Abstract + References | PDF (381 K)

4. K. Grasza, R. Schwarz, M. Laasch, K.W. Benz and M. Pawlowska. J. Crystal Growth 151 (1995), p. 261. SummaryPlus | Full Text + Links | PDF (438 K)

5. M. Laasch, R. Schwarz, W. Jorger, C. Eiche, M. Fiederle, K.W. Benz and K. Grasza. J. Crystal Growth 146 (1995), p. 125. Abstract | Abstract + References | PDF (328 K)

6. M. Laasch, G. Kloess, Th. Kunz, R. Schwarz, K. Grasza, C. Eiche and K.W. Benz. J. Crystal Growth 161 (1996), p. 34. Abstract | Abstract + References | PDF (316 K)

7. W. Palosz, K. Grasza, D. Gillies and G. Jerman. J. Crystal Growth 169 (1996), p. 20. Abstract | Abstract + References | PDF (686 K)

8. K. Grasza. J. Crystal Growth 146 (1995), p. 69. Abstract | Abstract + References | PDF (379 K)

9. K. Grasza. J. Crystal Growth 128 (1993), p. 609. Abstract-INSPEC | Abstract-Compendex  

10. K. Grasza and A. Jedrzejczak. J. Crystal Growth 162 (1996), p. 173. SummaryPlus | Full Text + Links | PDF (355 K)

11. W. Palosz, D. Gillies, K. Grasza, H. Chung, B. Raghothamachar and M. Dudley. J. Crystal Growth 182 (1997), p. 37. SummaryPlus | Full Text + Links | PDF (781 K)

12. K. Grasza. J. Crystal Growth 193 (1998), p. 426. SummaryPlus | Full Text + Links | PDF (215 K)

13. W. Palosz and H. Wiedemeier. J. Crystal Growth 129 (1993), p. 653. Abstract-Compendex | Abstract-INSPEC  

Corresponding author. Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland; email: grasza@ifpan.edu.pl