• Journal of Powder Materials
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• v.31 no.3
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• pp.226-235
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• 2024

InP quantum dots (QDs) have attracted researchers' interest due to their applicability in quantum dot light-emitting displays (QLED) or biomarkers for detecting cancers or viruses. The surface or interface control of InP QD core/ shell has substantially increased quantum efficiency, with a quantum yield of 100% reached by introducing HF to inhibit oxide generation. In this study, we focused on the control of bandgap energy of quantum dots by changing the Zn/(In+Zn) ratio in the In(Zn)P core. Zinc incorporation can change the photoluminescent light colors of green, yellow, orange, and red. Diluting a solution of as-synthesized QDs by more than 100 times did not show any quenching effects by the Förster resonance energy transfer phenomenon between neighboring QDs.

• Journal of the Korean Vacuum Society
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• v.15 no.2
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• pp.223-230
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• 2006

We have investigated the characteristics of hydrogen (H) plasma treated quantum dot infrared photodetectors (QDIPs). The structure used in this study consists of 3 stacked, self assembled $In_{0.5}Ga_{0.5}As/GaAs$ QD layer separated by GaAs barrier layers that were grown by molecular beam epitaxy. Optical characteristics of QDIPs, such as photoluminescence (PL) spectra and photocurrent spectra, have been studied and compared with each other for the as grown and H plasma treated QDIPs. H plasma treatment, resulted in the splitting of PL peak, which can be attributed to the redistribution of the size of QDs. The activation energies estimated from the temperature dependence of integrated PL intensity for as grown and H plasma treated QDIPs are found to be in good agreement with those determined from corresponding peaks of photocurrent spectra. It is also noted that photocurrent is detected up to 130 K for the H plasma treated QDIP, suggesting the future possibility for the development of infrared photodetectors with high temperature operation.

• Journal of the Korean Vacuum Society
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• v.15 no.2
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• pp.216-222
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• 2006

In this paper, we investigated the effect of hydrogen-plasma (H-plasma) treatment on the electrical and optical properties of a quantum dot infrared photodetector (QDIP) with a 5-stacked InAs dots in an InGaAs/GaAs well structure and $Al_{0.3}Ga_{0.7}As/GaAs$ SL (superlattice) current blocking layer. It has been observed that H-plasma treatment didn't affect the band structure of QDIP. It has been also observed that the H-plasma treatment on the QDIP not only enhance the electrical property of QDIP by curing the defect channels in $Al_{0.3}Ga_{0.7}As/GaAs$ SL but also introduce defects in QDIP structure. The H-plasma treatment for 10 min with 20 W of RF power provided the lowest dark current, which made it possible to measure the photo-current (PC) of QDIP whose PC was not detectable without the H-plasma treatment due to the high dark current.

• Journal of the Korean Vacuum Society
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• v.15 no.2
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• pp.209-215
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• 2006

We investigated the optical property and the electronic subband structure of InAs quantum dots in an InAsGa/GaAs well structure utilizing photoluminescence (PL), PL excitation (PLE) and near infrared transmission spectroscopy. From transmission and PLE spectra, we found three bound states in the InAs quantum dot and two bound states in InGaAs/GaAs quantum well, and correlated to the results of intersubband transitions observed in photocurrent spectrum.

• Journal of the Korean Vacuum Society
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• v.18 no.4
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• pp.266-271
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• 2009

We have investigated the lasing characteristics of GaAs-based 1300 nm wavelength region InAs Quantum Dot Laser Diode grown by Migration Enhanced Molecular Beam Epitaxy. Under a pulsed and CW operation, we observed the state switching of lasing wavelength from ground state (1302 nm) to excited state (1206 nm) due to the gain saturation of ground state. Under a pulsed operation, $J_{th}=92A/cm^2$, $\lambda_L=1311\;nm$ and under a CW operation, $J_{th}=247A/cm^2$, $\lambda_L=1320\;nm$.

• Proceedings of the Korean Vacuum Society Conference
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• 2007.02a
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• pp.117-117
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• 2007

• Proceedings of the Korean Vacuum Society Conference
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• 2007.08a
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• pp.269-269
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• 2007

• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.3137-3140
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• 2009

• Proceedings of the Korean Vacuum Society Conference
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• 2008.02a
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• pp.75-75
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• 2008

• Bulletin of Food Technology
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• v.22 no.3
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• pp.577-586
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• 2009