Spectroscopic ellipsometry study of barrier width effect in self-organized InGaAs/GaAs QDs laser diodes
By: Al-Ghamdi, M. S
.
Contributor(s): Sayari, A.
Publisher: New Delhi CSIR 2019Edition: Vol.57(10), Oct.Description: 725-731p.Subject(s): Humanities and Applied ScienceOnline resources: Click here
In:
Indian journal of pure & applied physics (IJPAP)Summary: Molecular beam epitaxy (MBE) is used to grow InGaAs/GaAs quantum dots (QDs) laser diodes (LDs) with different barrier widths (5, 10 and 15 nm) at 580 ºC on GaAs substrates. Optical properties of the InGaAs/GaAs QDs LDshave been investigated by using the spectroscopic ellipsometry (SE) technique. A general oscillator optical model has been utilized to fit the experimental data in order to obtain the LD layer thicknesses, refractive index and absorption coefficient. The dielectric function, the energy band gap and the surface and volume energy loss functions are computed in the energy range 1-6 eV. The optical properties of the deposited InGaAs/GaAs QDs LDs are found to be affected by the barrier width, which give more insight into carriers dynamics and optical parameters in these devices. The refractive indices, the extinction coefficients and the dielectric constants of the LDs with barrier widths 15 and 10 nm are relatively larger than those of the LD with barrier width 5 nm. These indicate that optical properties of LDs with larger barrier widths (15 and 10 nm) will be improved. The interbandtransition energies in the three devices have calculated and identified. Two energy gaps at 1.04 and ~1.37 eV are obtained for all the heterostructures which indicates thatfabricated LDs may be operating for a wavelength of 1.23 m at room temperature.
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School of Engineering & Technology Archieval Section | Not for loan | 2020707 |
Molecular beam epitaxy (MBE) is used to grow InGaAs/GaAs quantum dots (QDs) laser diodes (LDs) with different barrier widths (5, 10 and 15 nm) at 580 ºC on GaAs substrates. Optical properties of the InGaAs/GaAs QDs LDshave been investigated by using the spectroscopic ellipsometry (SE) technique. A general oscillator optical model has been utilized to fit the experimental data in order to obtain the LD layer thicknesses, refractive index and absorption coefficient. The dielectric function, the energy band gap and the surface and volume energy loss functions are computed in the energy range 1-6 eV. The optical properties of the deposited InGaAs/GaAs QDs LDs are found to be affected by the barrier width, which give more insight into carriers dynamics and optical parameters in these devices. The refractive indices, the extinction coefficients and the dielectric constants of the LDs with barrier widths 15 and 10 nm are relatively larger than those of the LD with barrier width 5 nm. These indicate that optical properties of LDs with larger barrier widths (15 and 10 nm) will be improved. The interbandtransition energies in the three devices have calculated and identified. Two energy gaps at 1.04 and ~1.37 eV are obtained for all the heterostructures which indicates thatfabricated LDs may be operating for a wavelength of 1.23 m at room temperature.
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