Large improvements in optoelectronic device performance are
expected as the amount of quantum confinement is increased. With quantum dots
(QDs), electrons and holes are confined on all sides which leads to the lowest-dimensional
quantum structure achievable. Our current quantum dots are composed of highly
strained GaInAs grown on GaAs which form via the Stranski-Krastanov growth mode.
This method has been shown to create this QDs via a self-assembled, in-situ
growth process. Our work in QDs has lead to high efficiency, high-speed photodetectors
operating at 1.06 mm.
[1,2] Work on these quantum dot structures is focused on the following aspects:
- Effect of growth temperature and starting template on QD formation and properties.
- Effect of growth method [Conventional vs. Migration-Enhanced Epitaxy (MEE)]
and growth structure on QD formation and properties
- Effect of indium concentration on QD formation and properties.
- Study of structural properties of QDs via x-ray diffraction and STM.
- Characterization of the optical properties of QDs via m
-PL and standard photoluminescence techniques
- Optimization of QDs for photodetector applications at 1.3 m
m.
This work is done in collaboration with Dr.
Joe C. Campbell of the Microelectronics
Research Center and Dr.
Ken Shih of the Physics Department
at UT-Austin.
References
[1] O. Baklenov, H. Nie, K. A. Anselm, J. C. Campbell, and B.
G. Streetman, “Multi-stacked quantum dot resonant-cavity photodetector operating
at 1.06 mm,” Electronics Letters, vol. 34, pp.
694-5, 1998.
[2] H. Nie, O. Baklenov, P. Yuan, C. Lenox, B. G. Streetman, and J. C. Campbell,
“Quantum-dot resonant-cavity separate absorption, charge, and multiplication
avalanche photodiode operating at 1.06 mm,”
IEEE Photonics Technology Letters, vol. 10, pp. 1009-11, 1998.