Abstract
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 language | English (US) |
---|---|
Pages (from-to) | 746-757 |
Number of pages | 12 |
Journal | IEEE Journal on Selected Topics in Quantum Electronics |
Volume | 4 |
Issue number | 4 |
DOIs | |
State | Published - Jul 1998 |
Keywords
- 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