Shidong Jiang

Nanowire crystals of a rigid rod conjugated polymer.

In this paper, we show that well-defined, highly crystalline nanowires of a rigid rod conjugated polymer, a poly(para-phenylene ethynylene)s derivative with thioacetate end groups (TA-PPE), can be obtained by self-assembling from a dilute solution. Structural analyses demonstrate the nanowires with an orthorhombic crystal unit cell wherein the lattice parameters are a approximately = 13.63 A, b approximately = 7.62 A, and c approximately = 5.12 A; in the nanowires the backbones of TA-PPE chains are parallel to the nanowire long axis with their side chains standing on the substrate. The transport properties of the nanowires examined by organic field-effect transistors (OFETs) suggest the highest charge carrier mobility approaches 0.1 cm(2)/(V s) with an average value at approximately 10(-2) cm(2)/(V s), which is 3-4 orders higher than that of thin film transistors made by the same polymer, indicating the high performance of the one-dimensional polymer nanowire crystals. These results are particular intriguing and valuable for both examining the intrinsic properties of PPEs polymer semiconductors and advancing their potential applications in electronic devices.

Solution-Processed, High-Performance Nanoribbon Transistors Based on Dithioperylene

Solution-processed, high-performance 1D single-crystalline nanoribbon transistors fabricated from dithioperylene are described. The integration of two sulfur atoms into the perylene skeleton induces a compressed highly ordered packing mode directed by S···S interactions. The mobilities of up to 2.13 cm(2) V(-1) s(-1) for a dithioperylene individual nanoribbon make it particularly attractive for electronic applications.

Pressure dependence of the intersubband transition in strained In0.15Ga0.85As/GaAs multiple quantum wells

The dependence of the intersubband transitions on pressure in strained In0.15Ga0.85As/GaAs multiple quantum wells has been studied in two samples with well widths of 8 and 15 nm, respectively, with photomodulated transmission spectroscopy by using a diamond anvil cell. The pressure coefficients of the energies for the intersubband transitions were found to depend significantly on the well widths and to be smaller than that of the band gap of constituents in bulk form. These results suggested that the critical thickness for strained In0.15Ga0.85As/GaAs layer should be smaller than 15 nm.

Photomodulated transmission spectroscopy of InxGa − xAsGaAs MQWs under hydrostatic pressure

Abstract We report the results of a comprehensive investigation of the dependence of various intersubband transitions within In x Ga 1 − x As GaAs multiple quantum wells (MQWs) on hydrostatic pressure. Several well-defined spectral features associated with the transitions of either heavy hole or light hole valence bands to the confined conduction subbands and the GaAs fundamental band gap transition are observed for all the samples under different pressures. It is demonstrated experimentally that the pressure coefficients for the intersubband transitions differ from that of the bulk counterparts in InxGa1 − xAs, and are both composition and well-width dependent. The physical reasons which may be responsible for the abnormal behavior of the pressure coefficients of the intersubband transitions in the MQWs are discussed.