Journal of the Korean Physical Society

, Volume 74, Issue 7, pp 713–717 | Cite as

Variations of Dark and Photo Currents of Metal-Semiconductor-Metal Photodetectors Fabricated on Ge Epilayer Grown on Si Substrate Caused by the Dimension of Interdigitated Pt Finger Electrodes

  • M. Zumuukhorol
  • S. Boldbaatar
  • Kyu-Hwan Shim
  • Chel-Jong ChoiEmail author
  • Z. Khurelbaatar
  • Sung-Nam Lee


Metal-semiconductor-metal (MSM) photodetectors (PDs) with interdigitated Pt finger electrodes were fabricated on Ge films grown epitaxially on a (100) Si substrate (Ge-on-Si) by rapid thermal chemical vapor deposition (RTCVD), and the effects of the finger dimensions on their optoelectrical properties were investigated. The two-step Ge heteroepitaxial growth technique through RTCVD, where a Ge seed layer was used in first-step growth at 350° C followed by second-step growth of a Ge film at high temperatures (500° C), led to the formation of a high-quality Ge epitaxial layer with excellent surface and interface morphologies. The dark current of Ge-on-Si MSM PD increased with decreasing finger width/spacing, which could be associated with electric field crowding near the contact electrode. As a result of the significant creation of electronhole pairs followed by their subsequent drift through the Ge epilayer toward the finger electrode, the Ge-on-Si MSM PDs exhibited a considerable spectral response to wavelengths in the range, 1530–1550 nm, regardless of the finger dimensions. A higher electric field was observed in the finger electrodes closer to each other, which enhanced the collection efficiency of the photo-generated carriers, which could be responsible for higher responsivity of Ge-on-Si MSM PDs with a smaller finger width/spacing.


Ge-on-Si Ge epilayer MSM Photodetector Dark current Responsivity 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.



This study was supported by the National Research Foundation of Korea (NRF) Grant (NRF-2017R1A2B2 003365) funded by the Ministry of Education, Republic of Korea, and by the Korea Basic Science Institute under the R&D program (Project No. C38521) supervised by the Ministry of Science and ICT, Republic of Korea.


  1. [1]
    A. Rogalski, Prog. Quantum Electron. 27, 59 (2003).ADSCrossRefGoogle Scholar
  2. [2]
    Z. Khurelbaatar et al., J. Korean Phys. Soc. 65, 2100 (2014).ADSCrossRefGoogle Scholar
  3. [3]
    T. Sugeta, T. Urisu, S. Sakata and Y. Mizushima, Jpn. J. Appl. Phys. 19, 459 (1980).CrossRefGoogle Scholar
  4. [4]
    J. Wang and S. Lee, Sensors 11, 696 (2011).CrossRefGoogle Scholar
  5. [5]
    G. Masini et al., Proc. SPIE 6898, 689808 (2008).CrossRefGoogle Scholar
  6. [6]
    Y. Ishikaw and K. Wada, IEEE Photon. J. 2, 306 (2010).ADSCrossRefGoogle Scholar
  7. [7]
    J. Michel, J. Liu and L. C. Kimerling, Nature Photon. 4, 527 (2010).ADSCrossRefGoogle Scholar
  8. [8]
    L. Colace, M. Gianlorenzo, F. Galluzzi and G. Assanto, Appl. Phys. Lett. 72, 33175 (1998).CrossRefGoogle Scholar
  9. [9]
    H. Zang et al., IEEE Electr. Device. L. 29, 161 (2008).ADSCrossRefGoogle Scholar
  10. [10]
    T. Asar and S. Ozcelik, Superlattices Microstruct. 88, 685 (2015).ADSCrossRefGoogle Scholar
  11. [11]
    L. Colace, G. Masini, F. Galluzzi and G. Assanto, Appl. Phys. Lett. 72, 3175 (1998).ADSCrossRefGoogle Scholar
  12. [12]
    A. K. Okyay, A. M. Nayfeh and K. C. Saraswat, Opt. Lett. 31, 2565 (2006).ADSCrossRefGoogle Scholar
  13. [13]
    Y. H. Kil et al., Mater. Sci. Semicond. 21, 58 (2014).CrossRefGoogle Scholar
  14. [14]
    D. J. Eaglesham and M. Cerullo, Phys. Rev. Lett. 64, 1943 (1990).ADSCrossRefGoogle Scholar
  15. [15]
    A. Satta et al., Mater. Sci. Semicond. Process. 9, 716 (2006).CrossRefGoogle Scholar
  16. [16]
    M. Zumuukhorol et al., Microelectron Reliab. 69, 60 (2017).CrossRefGoogle Scholar
  17. [17]
    L. Chen and M. Lipson, Opt. Express. 17, 7901 (2009).ADSCrossRefGoogle Scholar
  18. [18]
    H. D. Yang, V. Janardhanam, K. H. Shim and C. J. Choi, J. Nanosci. Nanotechnol. 14, 7683 (2014).CrossRefGoogle Scholar
  19. [19]
    Z. Z. Bandi, P. M. Bridger, E. C. Piquette and T. C. McGill, Appl. Phys. Lett. 72, 3166 (1998).ADSCrossRefGoogle Scholar
  20. [20]
    A. D. Kurtz, S. A. Kulin and B. L. Averbach, Phys. Rev. 101, 1285 (1956).ADSCrossRefGoogle Scholar
  21. [21]
    Y. S. Shin et al., Opt. Express 19, 6119 (2011)ADSCrossRefGoogle Scholar
  22. [22]
    V. Sorianello et al., Opt. Express 1, 856 (2011).CrossRefGoogle Scholar

Copyright information

© The Korean Physical Society 2019

Authors and Affiliations

  • M. Zumuukhorol
    • 1
  • S. Boldbaatar
    • 1
  • Kyu-Hwan Shim
    • 1
  • Chel-Jong Choi
    • 1
    Email author
  • Z. Khurelbaatar
    • 2
  • Sung-Nam Lee
    • 3
  1. 1.School of Semiconductor and Chemical Engineering, Semiconductor Physics Research CenterChonbuk National UniversityJeonjuKorea
  2. 2.School of Information and Communication TechnologyMongolian University of Science and TechnologyUlaanbaatarMongolia
  3. 3.Department of Nano-Optical EngineeringKorea Polytechnic UniversitySiheungKorea

Personalised recommendations