Far infrared (THz) electroluminescence from Si/SiGe quantum cascade heterostructures

S. A. Lynch, D. J. Paul, R. Bates, D. J. Norris, A. G. Cullis, Z. Ikonic, R. W. Kelsall, P. Harrison, D. D. Arnone, C. R. Pidgeon

Research output: Contribution to journalArticlepeer-review


There is strong interest in the development of sources that emit radiation in the far infrared (1-10 THz) frequency range for applications which include early detection of skin cancer, dental imaging, telecommunications, security scanning, gas sensing, astronomy, molecular spectroscopy, and the possible detection of biological weapons. While a number of THz sources are available, there are at present no compact, efficient, cheap and practical high-power solid-state sources such as light emitting diodes or lasers. Silicon is an excellent candidate for such a THz source since the lack of polar optical phonon scattering makes it an inherently low loss material at these frequencies. Furthermore, since over 97% of all microelectronics is presently silicon based, the realisation of a silicon based emitter/laser could potentially allow integration with conventional silicon-based microelectronics. In this paper THz electroluminescence from a Si/SiGe quantum cascade structure operating significantly above liquid helium temperatures is demonstrated. Fourier transform infrared spectroscopy was performed using step scan spectrometer with a liquid helium cooled Si-bolometer for detection. Spectra are presented demonstrating intersubband electroluminescence at a number of different frequencies. These spectral features agree very well with the theoretically calculated intersubband transitions predicted for the structure.

Original languageEnglish
Pages (from-to)140-149
Number of pages10
JournalProceedings of SPIE - the International Society for Optical Engineering
Issue number1
Publication statusPublished - 2002
EventOpto-Ireland 2002: Optics and Photonics Technologies and Applications - Galway, Ireland
Duration: 5 Sept 20026 Sept 2002


  • Electroluminescence
  • Germanium
  • Infrared
  • Quantum Cascade
  • Silicon
  • Terahertz


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