Growth and optical characterization

CEA

WSI, AUTH, JLU

The target of this work package is the synthesis of III-nitride based nano-objects, providing efficient room-temperature photoluminescence and high sensitivity towards variations in the surface potential. WP2 is strongly related to WP3 Structural characterization, which will provide valuable feedback on the atomic-scale structure of the nano-objects, and its correlation with growth conditions and luminescence properties. WP2 will provide as an output optimized structures that will be the material basis for QD-based transducers, to be processed and characterized by WP4. Feedback from the transducer characterization will also serve as an input for the optimization of the growth process. The nanostructure properties to be optimized are:

• Intense room-temperature luminescence;
• Adaptation of emission and detection wavelengths to commercially available emitters and detectors;
• Structural homogeneity;
• Sensitivity to variations in the surface potential.

To achieve optimized transducer structures the following approaches to nanostructure growth are chosen:

• self-assembled quantum dots obtained by the Stranski-Krastanow (SK) method on polar, semi- and non-polar surfaces(CEA).
• quantum dots formed inside nanorods (NRs), defined as nano-discs (NDs) (WSI).

The samples will be synthesized by plasma-assisted molecular beam epitaxy (PAMBE). The low growth temperature of this technique minimizes material inter-diffusion compared to ammonia-MBE or metalorganic vapor phase epitaxy. This feature, combined with the availability of powerful in-situ characterization techniques, allows to control the nanostructrure growth at the atomic scale.

• Task 2.1 Growth of self assembled (In)GaN QDs on polar surfaces (CEA)
• Task 2.2 Growth of self assembled (In)GaN QDs with reduced internal electric field (CEA)
• Task 2.3 Growth of (In)GaN QDs in nanorods (WSI)
• Task 2.4 Optical characterization (CEA, WSI, JLU)