Self-assembled integration technologies of silicon quantum dots toward future NeoSilicon quantum information devices

点击翻译按钮获取中文摘要

Nanocrystalline Si dots with a diameter of -8 nm were fabricated by using pulsed gas VHF plasma process and deposited on the substrate. We have successfully prepared the nc-Si dot dispersion solution by immersing the deposited wafer into alcohols with ultra sonic treatment. We then dropped a small volume of the solution onto other substrates and dried it. During the evaporation of alcohols the nc-Si dots were assembled in the solution via the lateral capillary meniscus force. Two-dimensional assembly of the dots was obtained by this method. Furthermore, we developped a new bottom-up technique for high-density assembly of the nc-Si quantum dots based on the Langmuir-Blodgett (LB) technique. We found that the solvent consists of chloroform (CHCl_3) and HMDS ([(CH_3)_3Si]_2NH) was suitable to the LB method for nc-Si. High density assembly of dots was obtained by using the LB method.We examined the assembly of the nc-Si dots on the silicon-on-insulator substrates with nanoscale patterning and succeeded in making the nc-Si dots cluster bridging between the nano-electrodes with a gap of as small as 20 nm. Combining the top-down nanolithography and bottom-up self-assembly may provide a new method to fabricate nanoscale Si structures for the future quantum information device applications. We also tried to integrate of nc-Si quantum dots with the single electron transistor (SET) A resist hole was prepared in the narrow region between the SET island and gate electrodes using the electron beam lithography. After the nc-Si deposition and lift-off processes, we observed that nc-Si QDs contacted directly to the substrate only in the resist hole area. From the equivalent circuit simulation and 3D capacitance analysis, we found that nc-Si QDs help to shift the Coulomb oscillation peak lines effectively and subtle charge polarization can be sensed as their remarkable shift.