Redshifting and broadening of quantum-well infrared photodetector's response via impurity-free vacancy disordering

Deepak Sengupta, Vikram Jandhyala, Sangsig Kim, Weich Fang, Jay Malin, Peter Apostolakis, Kwong Chi Hseih, Yia Chung Chang, Shun Lien Chuang, Sumith Bandara, Sarath Gunapala, Milton Feng, Eric Michielssen, Greg Stillman

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)


The partial intermixing of the well and barrier materials offers unique opportunities to shift locally the bandgap of quantum-well (QW) structures. We have demonstrated red-shifting and broadening of the wavelength responses of boundto-continuum GaAs and InP based quantum-well infrared photodetectors (QWIP's) after growth via impurity-free vacancy disordering (IFVD). A comprehensive set of experiments is conducted on QWIP's fabricated from both as-grown and multiple-quantum-well (MQW) structures. Compared to the as-grown detector, the peak spectral responses of the disordered detectors were shifted to longer wavelengths. The peak absolute response of the disordered GaAs based QWIP is lower by almost a factor of four. However, the responsivity characteristics of the disordered InP based QWIP show no major degradation. In general, with the spectral broadening taken into account, the overall performance of the disordered QWIP's has not dropped significantly. Thus, the postgrowth control of the QW composition profiles by impurity-free vacancy disordering offers unique opportunities to fine tune various aspects of a photodetector's response. Theoretical calculations of the absorption coefficient spectrum are in excellent agreement with the experimental data.

Original languageEnglish
Pages (from-to)746-757
Number of pages12
JournalIEEE Journal on Selected Topics in Quantum Electronics
Issue number4
Publication statusPublished - 1998 Jul
Externally publishedYes

Bibliographical note

Funding Information:
Manuscript received March 23, 1998; revised July 7, 1998. This work was supported by the NASA Office for Space Science and by the Microelectronics Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA. The work of D. Sengupta was supported under a fellowship by the National Academy of Sciences-National Research Council. The work of V. Jandhyala and E. Michielssen was supported by the Air Force Office of Scientific Research via the Multi University Research Initiative Program under Contract F49620-96-1-0025. This work was performed by the Center for Space Microelectronics Technology, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA.


  • Absolute response
  • Dark current characteristics
  • Focal plane array
  • Impurity-free vacancy disordering
  • Peak response wavelength
  • Quantum efficiency
  • Quantum-well infrared photodetectors
  • Rapid thermal annealing
  • Red shift

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering


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