The recent progress on Raman scattering in GaN single crystals and GaN/A1N heterostructures is re- viewed. Anti-Stokes Raman scattering is used to determine electron-phonon scattering time and decay time constant for ...The recent progress on Raman scattering in GaN single crystals and GaN/A1N heterostructures is re- viewed. Anti-Stokes Raman scattering is used to determine electron-phonon scattering time and decay time constant for longitudinal-opticat phonons. In a typical high electron mobility transistor based on GaN/A1N heterostructures, strong resonances are reached for the first-order and second-order Raman scattering processes. Therefore, both Stokes and anti-Stokes Raman intensities are dramatically enhanced. The feasibility for laser cooling of a nitride structure is studied. A further optimization will enable us to reach the threshold for laser cooling. Raman scattering have potential applications in up-conversion lasers and laser cooling of nitride ultrafast electronic and optoelectronic devices.展开更多
Capacitance is generally determined by the porous microstructure,electron conduction and the synergy effect of active sites in the porous electrode.In this work,we grew centimeter-scale metallic porous GaN single crys...Capacitance is generally determined by the porous microstructure,electron conduction and the synergy effect of active sites in the porous electrode.In this work,we grew centimeter-scale metallic porous GaN single crystals with conductivity up to 18 S/cm at room temperature.The Cu-catecholates(Cu–CAT)nanowire arrays were grown on porous GaN single crystal to form porous single-crystalline electrode with enhanced supercapacitor performance.The Cu–CAT/GaN single crystalline electrode exhibits specific capacitance of 216 F/g and normalized capacitance of 40μF/cm^(2).After 5000 cycles,it retains 80%of its initial capacitance.The porous single-crystalline GaN electrode has high porosity and excellent conductivity showing high surface capacitance.展开更多
文摘The recent progress on Raman scattering in GaN single crystals and GaN/A1N heterostructures is re- viewed. Anti-Stokes Raman scattering is used to determine electron-phonon scattering time and decay time constant for longitudinal-opticat phonons. In a typical high electron mobility transistor based on GaN/A1N heterostructures, strong resonances are reached for the first-order and second-order Raman scattering processes. Therefore, both Stokes and anti-Stokes Raman intensities are dramatically enhanced. The feasibility for laser cooling of a nitride structure is studied. A further optimization will enable us to reach the threshold for laser cooling. Raman scattering have potential applications in up-conversion lasers and laser cooling of nitride ultrafast electronic and optoelectronic devices.
基金supported by the National Key Research and Development Program of China(2017YFA0700102)Natural Science Foundation of China(91845202)+1 种基金Dalian National Laboratory for Clean Energy(DNL180404)Strategic Priority Research Program of Chinese Academy of Sciences(XDB2000000)。
文摘Capacitance is generally determined by the porous microstructure,electron conduction and the synergy effect of active sites in the porous electrode.In this work,we grew centimeter-scale metallic porous GaN single crystals with conductivity up to 18 S/cm at room temperature.The Cu-catecholates(Cu–CAT)nanowire arrays were grown on porous GaN single crystal to form porous single-crystalline electrode with enhanced supercapacitor performance.The Cu–CAT/GaN single crystalline electrode exhibits specific capacitance of 216 F/g and normalized capacitance of 40μF/cm^(2).After 5000 cycles,it retains 80%of its initial capacitance.The porous single-crystalline GaN electrode has high porosity and excellent conductivity showing high surface capacitance.
