Ultrahigh near infrared photoresponsive organic field-effect transistors with lead phthalocyanine/C 60 heterojunction on poly(vinyl alcohol) gate dielectric

Performances of photoresponsive organic field-effect transistors (photOFETs) operating in the near infrared (NIR) region utilizing SiO 2 as the gate dielectric is generally low due to low carrier mobility of the channel. We report on NIR photOFETs based on lead phthalocyanine (PbPc)/C 60 heterojunction with ultrahigh photoresponsivity by utilizing poly(vinyl alcohol) (PVA) as the gate dielectric. For 808 nm NIR illumination of 1.69 mW cm −2 , an ultrahigh photoresponsivity of 21 A W −1 , and an external quantum efficiency of 3230% were obtained at a gate voltage of 30 V and a drain voltage of 80 V, which are 124 times and 126 times as large as the reference device with SiO 2 as the gate dielectric, respectively. The ultrahigh enhancement of photoresponsivity is resulted from the huge increase of electron mobility of C 60 film grown on PVA dielectric. AFM investigations revealed that the C 60 film grown on PVA is ...

Lei Sun, Jianping Zhang, Feiyu Zhao, Xiao Luo, Wenli Lv, Yao li, Qiang Ren, Zhanwei Wen, Yingquan Peng and Xingyuan Liu

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Dual enhancement of light extraction efficiency of flip-chip light-emitting diodes with multiple beveled SiC surface and porous ZnO nanoparticle layer coating

A porous ZnO nanoparticle layer coating composed of columnar ZnO nanoparticle piles and a multiple-beveled substrate was used to enhance the light extraction efficiency of GaN-based flip-chip light-emitting diodes (FC-LEDs), which were grown on high-purity SiC substrates. The SiC substrate was multiple-beveled by fabricating an ‘X’ pattern on the face of it, followed by a deposition of a porous ZnO nanoparticle layer on the ‘X’-patterned surface. A porous ZnO nanoparticle layer was fabricated with gas phase cluster beam deposition in a glancing incidence. The incident angular-resolved light transmission of the ZnO nanostructure beyond the critical angle of total internal reflection (TIR) was greatly enhanced. The light output power of the LED was improved by nearly 60% compared to the original planar GaN-based LED on an SiC substrate (FC-SLED), which contained a significant enhancement supplemental to the 18% electroluminescence (EL) enhancement realized with the ‘X’-pattern beve...



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Active current gating in electrically biased conical nanopores

We observed that the ionic current through a gold/silicon nitride (Si 3 N 4 ) nanopore could be modulated and gated by electrically biasing the gold layer. Rather than employing chemical modification to alter device behavior, we achieved control of conductance directly by electrically biasing the gold portion of the nanopore. By stepping through a range of bias potentials under a constant trans-pore electric field, we observed a gating phenomenon in the trans-pore current response in a variety of solutions including potassium chloride (KCl), sodium chloride (NaCl), and potassium iodide (KI). A computational model with a conical nanopore was developed to examine the effect of the Gouy–Chapman–Stern electrical double layer along with nanopore geometry, work function potentials, and applied electrical bias on the ionic current. The numerical results indicated that the observed modulation and gating behavior was due to dynamic reorganization of the electrical double...

Samuel Bearden, Erik Simpanen and Guigen Zhang

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