Journal of the Korean Vacuum Society (한국진공학회지)

The Korean Vacuum Society (한국진공학회)
권호 표지
DOI QR코드

DOI QR Code

Optical Properties of InAs Quantum Dots Grown by Changing Arsenic Interruption Time

As 차단 시간 변화에 의한 InAs 양자점의 광학적 특성

  • Choi, Yoon Ho (Department of Physics, Kangwon National University) ;
  • Ryu, Mee-Yi (Department of Physics, Kangwon National University) ;
  • Jo, Byounggu (Division of Advanced Materials Engineering, Chonbuk National University) ;
  • Kim, Jin Soo (Division of Advanced Materials Engineering, Chonbuk National University)
  • Received : 2012.12.25
  • Accepted : 2013.03.11
  • Published : 2013.03.30
Download PDF
⟨ Previous Next ⟩

Abstract

The optical properties of InAs quantum dots (QDs) grown on GaAs substrates grown by molecular beam epitaxy have been studied using photoluminescence (PL) and time-resolved PL measurements. InAs QDs were grown using an arsenic interruption growth (AIG) technique, in which the As flux was periodically interrupted by a closed As shutter during InAs QDs growth. In this study, the shutter of As source was periodically opened and closed for 1 (S1), 2 (S2), or 3 s (S3). For comparison, an InAs QD sample (S0) without As interruption was grown in a pure GaAs matrix for 20 s. The PL intensity of InAs QD samples grown by AIG technique is stronger than that of the reference sample (S0). While the PL peaks of S1 and S2 are redshifted compared to that of S0, the PL peak of S3 is blueshifted from that of S0. The increase of the PL intensity for the InAs QDs grown by AIG technique can be explained by the reduced InAs clusters, the increased QD density, the improved QD uniformity, and the improved aspect ratio (height/length). The redshift (blueshift) of the PL peak for S1 (S3) compared with that for S0 is attributed to the increase (decrease) in the QD average length compared to the average length of S0. The PL intensity, PL peak position, and PL decay time have been investigated as functions of temperature and emission wavelength. S2 shows no InAs clusters, the increased InAs QD density, the improved QD uniformity, and the improved QD aspect ratio. S2 also shows the strongest PL intensity and the longest PL decay time. These results indicate that the size (shape), density, and uniformity of InAs QDs can be controlled by using AIG technique. Therefore the emission wavelength and luminescence properties of InAs/GaAs QDs can also be controlled.

Arsenic interruption growth (AIG)법을 이용하여 GaAs 기판에 성장한 InAs 양자점(quantum dots, QDs)의 광학적 특성을 PL (photoluminescence)과 time-resolved PL을 이용하여 분석하였다. AIG법은 InAs 양자점 성장 동안 In 공급은 계속 유지하면서 셔텨(shutter)를 이용해서 As 공급과 차단을 조절하는 방법이다. 본 연구에서는 As 공급과 차단을 1초(S1), 2초(S2), 또는 3초(S3) 동안 반복하여 성장한 InAs QDs과 As 차단 없이 성장한 기준시료(S0)를 사용하였다. AIG법으로 성장한 시료들의 PL 세기는 기준시료보다 모두 강하게 나타나고, As 차단 시간에 따라 PL 피크는 적색이동(redshifted) 또는 청색이동 (blueshifted)하여 나타났다. 기준시료 S0의 PL 피크와 비교하였을 때 S1의 PL 피크의 적색이동은 양자점 평균 길이가 S0보다 증가하였기 때문이며, S3의 청색이동은 양자점 평균 길이가 S0보다 감소하였기 때문이다. AIG법으로 성장한 QDs 시료들의 PL 세기의 증가는 cluster의 감소, 양자점 밀도의 증가, 균일도의 향상, 종횡비(aspect ratio) 향상으로 설명된다. 온도에 따른 PL 세기와 PL 피크 에너지, PL 소멸 시간과 발광 파장에 따른 PL 소멸 시간을 측정하였다. As 공급과 차단을 2초로 하였을 때 cluster는 전혀 나타나지 않았고 양자점의 밀도는 증가하였으며 균일도와 종횡비도 향상되었다. 또한 S2는 가장 강한 PL 세기와 가장 긴 소멸 시간을 나타내었다. 이러한 결과는 AIG법을 이용하여 InAs 양자점의 크기, 조밀도, 균일도, 종횡비 등을 조절하여 원하는 파장대의 양자점을 성장할 수 있으며 발광 특성도 향상시킬 수 있음을 확인하였다.

Keywords

References

  1. M. Asada, Y. Miyamoto, and Y. Suematsu, IEEE J. Quantum Electron. 22, 1915 (1986). https://doi.org/10.1109/JQE.1986.1073149
  2. Y. Nakata, K. Mukai, M. Sugawara, K. Ohtsubo, H. Ishikawa, and N. Yokoyama, J. Crystal Growth 208, 93 (2000). https://doi.org/10.1016/S0022-0248(99)00466-2
  3. A. D. Stiff, S. Krishna, P. Bhattacharya, and S. Kennerly, Appl. Phys. Lett. 79, 421 (2001). https://doi.org/10.1063/1.1385584
  4. A. Fiore, U. Oeserle, R. P. Stanlye, and M. Ilegems, IEEE Photon. Technol. Lett. 12, 1601 (2000). https://doi.org/10.1109/68.896320
  5. D. Zhou, P. E. Vullum, G. Sharma, S. F. Thomassen, R. Holmestad, T. W. Reenaas, and B. O. Fimland, Appl. Phys. Lett. 96, 083108 (2010). https://doi.org/10.1063/1.3309411
  6. H. W. Shin, J. W. Choe, J. O. Kim, S. J. Lee, C. S. Kim, and S. K. Noh, J. Korean Vacuum Soc. 20, 35 (2011). https://doi.org/10.5757/JKVS.2011.20.1.035
  7. D. Sreenivasan, J. E. M. Haverkort, T. J. Eijkemans, and R. Notzel, Appl. Phys. Lett. 90, 112109 (2007). https://doi.org/10.1063/1.2713803
  8. S. Kim, D. K. Oh, P. W. Yu, J. -Y. Leem, J. I. Lee, and C. R. Lee, J. Crystal Growth 261, 38 (2004). https://doi.org/10.1016/j.jcrysgro.2003.09.017
  9. L. M. Kong, J. F. Cai, Z. Y. Wu, Z. Gong, Z. C. Niu, and Z. C. Feng, Thin Solid Films 498, 188 (2006). https://doi.org/10.1016/j.tsf.2005.07.079
  10. J. S. Kim, C. -R. Lee, and S. U. Hong, J. Crystal Growth 305, 78 (2007). https://doi.org/10.1016/j.jcrysgro.2007.03.061
  11. J. W. Oh, S. R. Kwon, M. -Y. Ryu, B. Jo, and J. S. Kim, J. Korean Vaccum Soc. 20, 442 (2011). https://doi.org/10.5757/JKVS.2011.20.6.442
  12. H. Y. Kim, M. -Y. Ryu, and J. S. Kim, J. Lumine. 132, 1759 (2012). https://doi.org/10.1016/j.jlumin.2012.01.057
  13. H. J. Lee, M. -Y. Ryu, and J. S. Kim, J. Appl. Phys. 108, 093521 (2010). https://doi.org/10.1063/1.3506709
  14. H. J. Lee, M. -Y. Ryu, and J. S. Kim, J. Korean Vaccum Soc. 18, 474 (2009). https://doi.org/10.5757/JKVS.2009.18.6.474
  15. N. K. Cho, S. P. Ryu, J. D. Song, W. J. Choi, and J. I. Lee, Appl. Phys. Lett. 88, 133104 (2006). https://doi.org/10.1063/1.2189195
  16. V. D. Dasika, J. D. Song, W. J. Choi, N. K. Cho, J. I. Lee, and R. S. Goldman, Appl. Phys. Lett. 95, 163114 (2009). https://doi.org/10.1063/1.3243688
  17. B. Jo, C. -R. Lee, J. S. Kim, K. Pyun, S. K. Noh, J. S. Kim, J. -Y. Leem, and M. -Y. Ryu, J. Korean Phys. Soc. 60, 460 (2012). https://doi.org/10.3938/jkps.60.460
  18. S. R. Kwon, M. -Y. Ryu, and J. D. Song, J. Korean Vacuum Soc. 21, 342 (2012). https://doi.org/10.5757/JKVS.2012.21.6.342