Volume 108, Issue 10, 15 November 2010
Index of content:
108(2010); http://dx.doi.org/10.1063/1.3496619View Description Hide Description
The use of graphenes relies largely on their optical detection with Fabry–Pérot type structures. We demonstrate here that optical reflection mode imaging with single graphenes on the bottom of a bare transparent substrate such as mica can provide a high contrast of more than 12% for visible light. This can be explained with the destructive interference of light reflected from the substrate-graphene and graphene-air interfaces, similarly to black soap films. Since the contrast is only weakly wavelength dependent, white light contrast of single graphenes is sufficiently high to be easily detected with a human eye. We argue that with the graphene on the bottom of the transparent substrate high contrasts for single graphenes can also be achieved on other transparent substrates exhibiting a broad range of refractive indices.
108(2010); http://dx.doi.org/10.1063/1.3505638View Description Hide Description
High-resolution synchrotron x-ray diffraction and field emission-scanning electron microscopy were used to investigate domain structures of the unpoled (001)-oriented (PZN–10.5%PT) single crystal. The results revealed the coexistence of 180° and 90° tetragonal nanotwin domains at room temperature. Upon zero-field heating, the PZN–10.5%PT undergoes a tetragonal-to-cubic transformation near . Tetragonal PZN–10.5%PT crystal has better thermal stability notably in the temperature range of . This makes the tetragonal PZN–PT potential candidates for high temperature piezoelectric devices.
Characterization of traps in the gate dielectric of amorphous and nanocrystalline silicon thin-film transistors by 1/f noise108(2010); http://dx.doi.org/10.1063/1.3506527View Description Hide Description
The low frequency noise technique is used to obtain the volume profile of traps in the gate dielectric of hydrogenated amorphous silicon (a-Si:H) and nanocrystallinesilicon (nc-Si:H) thin film transistors(TFTs). In both a-Si:H and nc-Si:H TFTs, within the range of probing depth in the gate dielectric, the traps have a uniform spatial distribution which is consistent with the observed pure 1/f noise. The experimental results show that the gate dielectric trap properties near the interface are dependent on the channel material with the trap density in nc-Si:H TFTs being much smaller in comparison with the a-Si:H TFTs.