Investigation of quantum-confinement effect and Stokes shift in strained Ga1−xInxN/GaN double quantum wells by spectroscopic ellipsometry and photoluminescence
- 16 April 2001
- journal article
- Published by AIP Publishing in Applied Physics Letters
- Vol. 78 (16) , 2366-2368
- https://doi.org/10.1063/1.1355987
Abstract
The evolution of the optical absorption and emission properties of strained Ga1−xInxN/GaN double quantum wells grown on (0001)-oriented sapphire substrates with varying well width has been investigated by spectroscopic ellipsometry (SE) and photoluminescence (PL). The SE result shows that the band-gap absorption energy of the wells shifts to higher energies as the well width decreases, indicating a quantum-confinement effect. The decreasing trend agrees with the result of one-dimensional square-well potential calculations. The PL result shows a Stokes shift of the emission edge from the corresponding absorption edge, attributable to the combined effects of the strain-induced piezoelectric potential and the In-fluctuation potential in the well. The blueshift of the emission edge with increasing PL excitation density further supports the existence of a strong piezoelectric field in the well.Keywords
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