To improve absorption of quantum well infrared photodetectors (QWIPs),a coupling layer with metallic grating is designed and fabricated above the quantum well.The metal grating is composed of 100 nm Au film on top,and...To improve absorption of quantum well infrared photodetectors (QWIPs),a coupling layer with metallic grating is designed and fabricated above the quantum well.The metal grating is composed of 100 nm Au film on top,and a 20-nm Ti thin layer between the Au film and the sapphire substrate is coated as an adhesion/buffer layer.To protect the photodetector from oxidation and to decrease leakage,a SiO_(2) film is deposited by neans of plasmaenhanced chemical vapor deposition.A value of about 800nm is an optimized thickness for the SiO2 applied in the metallic grating-based mid-infrared QWIP.In addition,a QWIP passivation layer is studied experimentally.The results demonstrate that the contribution from the layer is positive for metal grating coupling with the quantum well.The closer the permittivity of the two dielectric layers (SiO_(2) and the passivation layers),and the closer the two transmission peaks,the greater the QWIP enhancement will be.展开更多
Plasmonic structural colors have plenty of advantages over traditional colors based on colorants.The pulsed laser provides an important method generating plasmonic structural colors with high efficiency and low cost.H...Plasmonic structural colors have plenty of advantages over traditional colors based on colorants.The pulsed laser provides an important method generating plasmonic structural colors with high efficiency and low cost.Here,we present plasmonic color printing Al nanodisc structures through curvature-driven shape transition.We systematically study the mechanism of morphologic evolution of the Al nanodisc below the thermal melting threshold.A multi-pulse-induced accumulated photothermal effect and subsequent curvature-driven surface atom diffusion model are adopted to explain the controllable shape transition.The shape transition and corresponding plasmonic resonances of the nanodisc can be independently and precisely modulated by controlled irradiations.This method opens new ways towards high-fidelity color prints in a highly efficient and facile laser writing fashion.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 60877021,09EF011001 and 61077010.
文摘To improve absorption of quantum well infrared photodetectors (QWIPs),a coupling layer with metallic grating is designed and fabricated above the quantum well.The metal grating is composed of 100 nm Au film on top,and a 20-nm Ti thin layer between the Au film and the sapphire substrate is coated as an adhesion/buffer layer.To protect the photodetector from oxidation and to decrease leakage,a SiO_(2) film is deposited by neans of plasmaenhanced chemical vapor deposition.A value of about 800nm is an optimized thickness for the SiO2 applied in the metallic grating-based mid-infrared QWIP.In addition,a QWIP passivation layer is studied experimentally.The results demonstrate that the contribution from the layer is positive for metal grating coupling with the quantum well.The closer the permittivity of the two dielectric layers (SiO_(2) and the passivation layers),and the closer the two transmission peaks,the greater the QWIP enhancement will be.
基金the National Key R&D Program of China(No.YS2018YFB110012)the Guangdong Provincial Innovation and Entrepreneurship Project(No.2016ZT06D081)。
文摘Plasmonic structural colors have plenty of advantages over traditional colors based on colorants.The pulsed laser provides an important method generating plasmonic structural colors with high efficiency and low cost.Here,we present plasmonic color printing Al nanodisc structures through curvature-driven shape transition.We systematically study the mechanism of morphologic evolution of the Al nanodisc below the thermal melting threshold.A multi-pulse-induced accumulated photothermal effect and subsequent curvature-driven surface atom diffusion model are adopted to explain the controllable shape transition.The shape transition and corresponding plasmonic resonances of the nanodisc can be independently and precisely modulated by controlled irradiations.This method opens new ways towards high-fidelity color prints in a highly efficient and facile laser writing fashion.
