Photo-origami—Bending and folding polymers with light

Jennie Ryu, Matteo D’Amato, Xiaodong Cui, Kevin N. Long, H. Jerry Qi, and Martin L. Dunn

An idea based on the traditional Japanese art of paper-folding, optical origami uses light to enable controllable, sequenced, macroscopic bending and folding of organic polymers. The technique uses embedded mechanical and optical fields as actuators that can be used to manipulate the polymer sheets.

Appl. Phys. Lett. 100, 161908 (2012)
Read the press release: [Optical Origami, Ian S. Osborne] www.sciencemag.org

Physics of ultra-high bioproductivity in algal photobioreactors

Efrat Greenwald, Jeffrey M. Gordon, and Yair Zarmi

Traditional microalgae production generally performs well below the fundamental bioproductivity limits. This paper describes a model for photobioreactors that can produce order-of-magnitude increases in bioproductivity, with applications in pharmaceuticals, wastewater treatment, and biofuels.

Appl. Phys. Lett. 100, 143703 (2012)

Fast programming metal-gate Si quantum dot nonvolatile memory using green nanosecond laser spike annealing

Yu-Chung Lien, Jia-Min Shieh, Wen-Hsien Huang, Cheng-Hui Tu, Chieh Wang, Chang-Hong Shen, Bau-Tong Dai, Ci-Ling Pan, Chenming Hu, and Fu-Liang Yang

Researchers present an ultrafast nonvolatile memory solution. The memory, based on silicon quantum dot-embedded dielectrics, resists degradation whilst maintaining fast programming with low operating voltages, and can be integrated into current production processes.

Appl. Phys. Lett. 100, 143501 (2012)

X-ray pulse preserving single-shot optical cross-correlation method for improved experimental temporal resolution

M. Beye, O. Krupin, G. Hays, A. H. Reid, D. Rupp, S. de Jong, S. Lee, W.-S. Lee, Y.-D. Chuang, R. Coffee, J. P. Cryan, J. M. Glownia, A. Föhlisch, M. R. Holmes, A. R. Fry, W. E. White, C. Bostedt, A. O. Scherz, H. A. Durr, and W. F. Schlotter

The authors measured the relative arrival time between an optical pulse and a soft x-ray pulse from a free-electron laser. These time resolution of pump-probe experiments at LCLS were improved at least by a factor of two to 130 fs (FWHM). The results achieved with this method present a clear path toward temporal resolutions below 100 fs.

Appl. Phys. Lett. 100, 121108 (2012)

Electric field effects in low resistance CoFeB-MgO magnetic tunnel junctions with perpendicular anisotropy

H. Meng, R. Sbiaa, M. A. K. Akhtar, R. S. Liu, V. B. Naik, and C. C. Wang

Investigations the electric field effects in low resistance perpendicular magnetic tunnel junction (MTJ) devices found that the electric field can effectively reduce the coercivity (H_c) of free layer (FL) by 30% for a bias voltage (V_b) of −0.2V. This is in in contrast to a much less sensitive of H_c to V_b for the reference layer (RL). The authors argue these findings are be important for memory technologies.

Appl. Phys. Lett. 100, 122405 (2012)

Flexible solid-state paper based carbon nanotube supercapacitor

Shan Hu, Rajesh Rajamani, and Xun Yu

A flexible solid-state supercapacitor of high energy density is developed using single-wall carbon nanotubes (SWNT)-coated cotton paper as electrodes and solid-state PVA/phosphoric acid as electrolyte. According to the authors, the performance is comparable to that of commercial supercapacitor and offer several significant advantages for use in hybrid electric vehicles.

Appl. Phys. Lett. 100, 104103 (2012) | Read the press release: physorg.com

Electron drift-mobility measurements in polycrystalline CuIn_1−xGa_xSe₂ solar cells

S. A. Dinca, E. A. Schiff, W. N. Shafarman, B. Egaas, R. Noufi, and D. L. Young

Photocarrier time-of-flight (TOF) measurements of electron drift-mobilities in p-type CIGS thin films incorporated into solar cells are reported. The electron mobilities are lower than the range of electron Hall mobilities reported for n-type polycrystalline thin films and single crystals. It is proposed that the electron drift mobilities are properties of disorder-induced mobility edges and this disorder could increase cell efficiencies.

Appl. Phys. Lett. 100, 103901 (2012)

Metal-oxide-semiconductor field effect transistor humidity sensor using surface conductance

Seok-Ho Song, Hyun-Ho Yang, Chang-Hoon Han, Seung-Deok Ko, Seok-Hee Lee, and Jun-Bo Yoon

A very sensitive MOSFET humidity sensor, which does not need any specific materials to sense the humidity in the air, is presented. The sensor makes use of the surface conductance change in the low pressure chemical vapor deposited (LPCVD) silicon dioxide.

Appl. Phys. Lett. 100, 101603 (2012)

Scaling of Al₂O₃ dielectric for graphene field-effect transistors

B. Fallahazad, K. Lee, G. Lian, S. Kim, C. M. Corbet, D. A. Ferrer, L. Colombo, and E. Tutuc

The scaling of Al₂O₃ dielectric on graphene by atomic layer deposition (ALD) using ultra-thin, oxidized Ti and Al films as nucleation layers was studied. The nucleation layer was found to have a significant impact on the dielectric constant and morphology. TEM analysis showed that the nucleation layer yields an amorphous film, whereas the Ti nucleation layer yielded a partially crystalline film.

Appl. Phys. Lett. 100, 093112 (2012)

Enhanced spin pumping at yttrium iron garnet/Au interfaces

C. Burrowes, B. Heinrich, B. Kardasz, E. A. Montoya, E. Girt, Yiyan Sun, Young-Yeal Song, and Mingzhong Wu

Using ferromagnetic resonance, the authors studied spin injection across the ferrimagnetic insulator yttrium iron garnet (YIG)/normal metal Au. It is shown that the spin pumping efficiency can be improved by chemical modification of the YIG interface, using standard etching tools prior to deposition of metallic films.

Appl. Phys. Lett. 100, 092403 (2012)