| As the device miniaturization is becoming the hotspot in the integrated optoelectronics and its related fields, micro/nanostructured devices with three-dimensional (3D) structures will exhibit significant advantages by virtue of excellent structural and physical properties.Compared with the traditional two-dimensional planar structure, the microtube, as a typical three-dimensional structure device, has not only hollow features but also good optical and electrical properties, which shows a good application prospects in optical and electrical device fabrication, microfluidic sensing and other frontier fields. In addition,since self-rolled-microtubes were characterized by integrated controllability, integration with the gain medium, such as quantum dots(QDs), can lead to the conversion of self-rolled-microtubes to device fabrication. The fabrication of 3D structures related to self-rolled-microtube is of great value for integrated optoelectronics and large-scale microfluidic integration.In this paper, the epitaxial structure of the microtube is grown on the GaAs substrate. After the monolayer QDs were embedded in the strained layer and the AlGaAs SCH was planted, the self-rolled-microtube was fabricated by lithography and etching. And a ?PL test is performed to determine whether or not a Whispering Gallery Mode (WGM) is obtained.In order to achieve the WGM and improve the quality factor of the optical resonator, we try to transfer the microtube to other substrates, and achieved microtube suspension, the Q value is improved. Then we can explore the preparation of related devices. In addition, with Au nanoparticles (Au-NPs) assisted microtube curl, a new method of adjusting the diameter of microtube is developed. Surface-enhanced raman scattering (SERS ) was obtained by titration of rhodamine solution on the GaAs planar substrate attached silver nanoparticles. The main work and achievements include the following points:1. In the InGaAs/GaAs strained-layers structure, single QDs are embedded and AlGaAs SCH is introduced, and microtube is fabricated using this epitaxial structure. After the microtubes were transferred to the GaAs substrate with gold film and the SiOx substrate respectively, the WGM was obtained by test. In order to further improve the Q value of the resonator, we have fabricated the self-rolled-microtube by U-mesa, achieved microtube suspend on the substrate with gold plating, and etching substrate to increase the floating distance. The optical properties of the microtubes obtained by these methods are tested, and optical resonant modes are obtained.Quality factor of the microtube resonator can reach about 1000. The fabrication of active microcavity of self-rolled-microtube was realized,which lays a foundation for the further study of tubular functional device.2. 2 nm gold films were deposited on the InGaAs/GaAs strained bilayer structure, and annealed at 650 degrees for 300s to form Au nanoparticles. The diameter of the microtube with nanoparticles is reduced. It was found that the surface tension of the epitaxial structure was changed by the implantation of Au-NPs, resulting in the reduction of the diameter of the microtube from the initial 2.7?m to 2.4?m. Through metal nanoparticles assisted roll up tubes, we get a simple way to reduce the diameter of the microtube.3. Exploration of fabricating rolled-up field effect transistor (RUFET).The epitaxial substrates were grown by molecular beam epitaxy(MBE) and the layout was designed according to the fabrication process. The exploration of corrosion conditions and the related work such as plating electrodes were explored.4. Ag film with a thickness of 2 nm was deposited on the planar GaAs substrate. After annealing at 500 degrees for 80s, the Ag nanoparticles with favourable morphology were prepared. The titration of 10-5M rhodamine solution R-6G on a substrate with Ag particles was realized. SERS was detected obviously, which laid a foundation for the preparation of SERS substrate. |
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