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We present the magneto-optical investigation of coupling between single exciton spin state of an InGaAs QD and a high quality micropillar cavity. Due to Purcell effect, we realize the selective enhancement of spin polarized photon emission from a single quantum dot-micropillar cavity system by tuning external magnetic field.
Mid-infrared emission with high efficiency was achieved for InAsSb quantum dots by using InGaAsSb sandwich layers and InP carrier blocking layers. As a result of reduced quantum confinement and lattice mismatch around InAsSb quantum dots caused by InGaAsSb layers, an emission of 2.1 μm was obtained for the sample with In0.53Ga0.47As0.25Sb0.75 layers. The emission signal was observed up to 330 K by...
Quantum dot intermixing is a post-growth approach to tuning optoelectronic devices. SiO2 capping layers can enhance these effects through impurity-free vacancy disordering, whereas TiO2 caps can decrease intermixing. In this study, multi-colour quantum dot infrared photodetectors were fabricated through selective intermixing and four different encapsulants were investigated.
Performances of GaAs reference solar cells and 10-layer InGaAs/ GaAs quantum dot solar cells were tested using AM1.5 illumination with results indicate that quantum dot (QD) structures improve the photo-current density compared to reference devices. Systematic measurements of the dark current versus voltage (I-V) characteristics were also carried out as a function of temperatures from 30K to 310K...
This paper investigated the temperature effect on the electrical properties of an In0.5Ga0.5As/GaAs QD solar cell, leading to a better understanding of the basic cell characteristics influenced by QD incorporation which is of great importance for future design of high efficiency QD solar cells.
We discuss the role of stress on diffusion of vacancies and interstitials theoretically. The stresses induced by SiO2 and TiO2 dielectric layers on InP and GaAs based QD structures are calculated and some reported quantum dot intermixing results are explained by a stress-induced forced interdiffusion model.
In this talk, main activities and progress in the areas of compound semiconductor quantum dots and nanowires, and device integration in Semiconductor Optoelectronics and Nanotechnology Group at the Australian National University will be addressed.
We present results on integrated photonic devices fabricated using InGaAs quantum-dots. Selective-area MOCVD is used to grow the active region with quantum dots emitting at different wavelengths for fabrication of the integrated devices
In this work, rapid thermal annealing was performed on InGaAs/GaAs quantum dot infrared photodetectors (QDIPs) at different temperatures. The photoluminescence showed a blue-shifted wavelength and the spectral response exhibited red-shift from the annealed QDIPs in comparison with the as-grown sample. The overall device performance was not affected by low annealing temperature however for high annealing...
The performance characteristics of InGaAs/GaAs quantum-dots-in-a-well infrared photodetectors grown by MOCVD are reported. A responsivity of 40mA/W at the peak detectivity of 3.2 109 cmHz/W has been achieved at a temperature of 77K. In an effort to understand the spectral behavior of the characterized devices band structure modeling has been performed.
InGaAs quantum dots (QDs) and nanowires have been grown on GaAs by metal-organic chemical vapour deposition on GaAs (100) and (111)B substrates, respectively. InGaAs QD lasers were fabricated and characterised. Results show ground-state lasing at about 1150 nm in devices with lengths greater than 2.5 mm. We also observed a strong influence of nanowire density on nanowire height specific to nanowires...
The role of increasing GaAs thickness (0-3 nm) to improve the optical quality and tune the emission wavelength of InAs quantum dots (QDs) grown on GaInAsP buffer on (100) InP substrate by metalorganic chemical vapor deposition was studied. The growth of a very thin (0.3 nm-0.6 nm) GaAs interlayer between GaInAsP buffer and InAs QDs layer reduced the mean height and size fluctuation of InAs QDs by...
We demonstrate that selective-area-epitaxy can be used to selectively tune the properties of InGaAs quantum-dots in different regions of the same wafer. We report single step, MOCVD growth of different sized dots, luminescing at wavelengths spread over a range of 100 nm
InAs/GaAs quantum dots (QDs) were grown by low pressure metal-organic chemical vapour deposition in the Stranski-Krastanow growth mode. We describe the influence of growth parameters such as coverage, the V/III ratio, growth temperature and growth interrupts on the QD nucleation and the importance of avoiding formation of larger islands which are particularly susceptible to dislocations. After an...
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