A high open-circuit voltage betavoltaic microbattery based on a GaN p-i-n diode is demonstrated.Under the irradiation of a 4×4 mm^(2) planar solid 63Ni source with an activity of 2 mCi,the open−circuit voltage Vo...A high open-circuit voltage betavoltaic microbattery based on a GaN p-i-n diode is demonstrated.Under the irradiation of a 4×4 mm^(2) planar solid 63Ni source with an activity of 2 mCi,the open−circuit voltage Voc of the fabricated single 2×2 mm^(2) cell reaches as high as 1.62 V,the short−circuit current density Jsc is measured to be 16nA/cm^(2).The microbattery has a fill factor of 55%,and the energy conversion efficiency of beta radiation into electricity reaches to 1.13%.The results suggest that GaN is a highly promising potential candidate for long-life betavoltaic microbatteries used as power supplies for microelectromechanical system devices.展开更多
This paper studies the exciton-longitudinal-optical-phonon coupling in InGaN/GaN single quantum wells with various cap layer thicknesses by low temperature photoluminescence (PL) measurements. With increasing cap la...This paper studies the exciton-longitudinal-optical-phonon coupling in InGaN/GaN single quantum wells with various cap layer thicknesses by low temperature photoluminescence (PL) measurements. With increasing cap layer thickness, the PL peak energy shifts to lower energy and the coupling strength between the exciton and longitudinal- optical (LO) phonon, described by Huang-Rhys factor, increases remarkably due to an enhancement of the internal electric field. With increasing excitation intensity, the zero-phonon peak shows a blueshift and the Huang-Rhys factor decreases. These results reveal that there is a large built-in electric field in the well layer and the exciton-LO-phonon coupling is strongly affected by the thickness of the cap layer.展开更多
Generally, nanoparticles are easy to aggregate due to their nano sizes, which influence the physical and chemical properties. In this work, a dispersion treatment of the TiO2 nanoparticles with different average sizes...Generally, nanoparticles are easy to aggregate due to their nano sizes, which influence the physical and chemical properties. In this work, a dispersion treatment of the TiO2 nanoparticles with different average sizes was employed to improve the dispersion of TiO2 nanoparticles, in order to prepare flexible photoanodes for dye-sensitized solar cells (DSCs) with novel photovoltaic properties at a low temperature. The effects of dispersion treatment on the dispersion of TiO2 nanoparticles, including the viscosities of the binder-free TiO2 paste, the morphologies and textural properties of nanoparticle-TiO2 films, and the photovoltaic properties of the flexible DSCs, were investigated. Flexible indium-tin oxide (ITO)-coated polyethylene naphthalate (PEN) substrates with sputter deposited Pt were employed as the transparent flexible counter electrodes. A short-circuit photocurrent density of 9.62 mA·cm 2, an open-circuit voltage of 0.757 V, a fill factor of 0.589 and an overall light-to-energy conversion efficiency of 4.29% for the flexible DSCs under AM1.5 illumination of 100 mW cm 2 were obtained with dispersion treatment. A 30.8% increment of the energy conversion efficiency for DSCs made by dispersion treatment was obtained compared with that made without dispersion treatment.展开更多
基金by the National Natural Science Foundation of China(No 51075344)Natural Science Foundation of Fujian Province(No 2010J01015).
文摘A high open-circuit voltage betavoltaic microbattery based on a GaN p-i-n diode is demonstrated.Under the irradiation of a 4×4 mm^(2) planar solid 63Ni source with an activity of 2 mCi,the open−circuit voltage Voc of the fabricated single 2×2 mm^(2) cell reaches as high as 1.62 V,the short−circuit current density Jsc is measured to be 16nA/cm^(2).The microbattery has a fill factor of 55%,and the energy conversion efficiency of beta radiation into electricity reaches to 1.13%.The results suggest that GaN is a highly promising potential candidate for long-life betavoltaic microbatteries used as power supplies for microelectromechanical system devices.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60876007 and 10974165)the Research Program of Xiamen Municipal Science and Technology Bureau,China (Grant No. 2006AA03Z110)
文摘This paper studies the exciton-longitudinal-optical-phonon coupling in InGaN/GaN single quantum wells with various cap layer thicknesses by low temperature photoluminescence (PL) measurements. With increasing cap layer thickness, the PL peak energy shifts to lower energy and the coupling strength between the exciton and longitudinal- optical (LO) phonon, described by Huang-Rhys factor, increases remarkably due to an enhancement of the internal electric field. With increasing excitation intensity, the zero-phonon peak shows a blueshift and the Huang-Rhys factor decreases. These results reveal that there is a large built-in electric field in the well layer and the exciton-LO-phonon coupling is strongly affected by the thickness of the cap layer.
基金supported by the National High Technology Research and Development Program of China (Grant No. 2011AA-050522)Sanjiang-yuan Scientific Program of Qinghai Science & Technology Department(Grant No. 2010-N-S03)the Ministry of Science & Technology (MOST) International S&T Cooperation Program of China (Grant No. 2010DFA-64360)
文摘Generally, nanoparticles are easy to aggregate due to their nano sizes, which influence the physical and chemical properties. In this work, a dispersion treatment of the TiO2 nanoparticles with different average sizes was employed to improve the dispersion of TiO2 nanoparticles, in order to prepare flexible photoanodes for dye-sensitized solar cells (DSCs) with novel photovoltaic properties at a low temperature. The effects of dispersion treatment on the dispersion of TiO2 nanoparticles, including the viscosities of the binder-free TiO2 paste, the morphologies and textural properties of nanoparticle-TiO2 films, and the photovoltaic properties of the flexible DSCs, were investigated. Flexible indium-tin oxide (ITO)-coated polyethylene naphthalate (PEN) substrates with sputter deposited Pt were employed as the transparent flexible counter electrodes. A short-circuit photocurrent density of 9.62 mA·cm 2, an open-circuit voltage of 0.757 V, a fill factor of 0.589 and an overall light-to-energy conversion efficiency of 4.29% for the flexible DSCs under AM1.5 illumination of 100 mW cm 2 were obtained with dispersion treatment. A 30.8% increment of the energy conversion efficiency for DSCs made by dispersion treatment was obtained compared with that made without dispersion treatment.