Local fluctuations in the distribution of dopant atoms are thought to cause the nanoscale electronic disorder or phase separation in pnictide superconductors. Atom probe tomography has enabled the first direct observations of dopant species clustering in a K-doped 122-phase pnictide. First-principles calculations suggest the coexistence of static magnetism and superconductivity on a lattice par...

Silicon nanowires are expected to have applications in transistors, sensors, resonators, solar cells and thermoelectric systems. Understanding the surface properties and dopant distribution will be critical for the fabrication of high-performance devices based on nanowires. At present, determination of the dopant concentration depends on a combination of experimental measurements of the mobilit...

Silicon field-effect transistors have now reached gate lengths of only a few tens of nanometers, containing a countable number of dopants in the channel. Such technological trend brought us to a research stage on devices working with one or a few dopant atoms. In this work, we review our most recent studies on key atom devices with fundamental structures of silicon-on-insulator MOSFETs, such as...

Guest-host interactions have been examined experimentally for amorphous solid water (ASW) films doped with CO2 or N2O. The main diagnostics are Fourier transform infrared (FTIR) spectroscopy and temperature programmed desorption (TPD). ASW films deposited at 90 K are exposed to a dopant, and the first molecules that attach to a film enter its bulk until it is saturated with them. Subsequent dop...

Cholesteric liquid crystals (CLCs) are self-organized helical nano-structures that selectively reflect certain wavelength of a circularly polarized light. For most CLCs, the handedness is fixed once a chiral dopant is employed. Here, we report a handedness-invertible CLC through opposite-handed doping of a photo-sensitive chiral azobenzene dopant and a photo-stable chiral dopant. With high solu...

Chemical doping in p-conjugated organic semiconductors, which involves a redox reaction between a host p-conjugated material and a dopant, is achieved by either co-evaporation, co-dissolved solution, or exposure to a dopant gas. Here, we demonstrate a new route for molecular doping; a thiophene-based semiconducting polymer film can be doped with dopants dispersed in an orthogonal solvent. An in...

Compound semiconductor devices, as typified by laser diodes, photo diodes, and high electron mobility transistors, are used for optical communication systems, satellite communications, and cellular base stations to meet a growing demand for large-capacity and high-speed communication systems that play a key role in the infrastructure of modern society. The properties and reliability of semicond...

From New York University School of Medicine, Department of Ophthalmology, New York, New York (ET); and Ivey Eye Institute, Western University, London, Ontario, Canada (CH). The authors have no financial or proprietary interest in the materials presented herein. Correspondence: Edmund Tsui, MD, New York University School of Medicine, Department of Ophthalmology, 462 First Avenue, NBV 5N18, New Y...

In this work, two p-cyanophenyl end-capped oligothiophenes, and , were compared as dopants in the P3HT:PC60BM bulk heterojunction (BHJ) layer of inverted organic solar cells. Inclusion of significantly increased the average efficiency of the solar cells, while the increase using doping in the cell efficiency was minor. In the BHJ photoactive layer, the dopant molecules are close to and interact...

A centrality measure based on the time of first returns rather than the number of steps is developed and applied to finding proton traps and access points to proton highways in the doped perovskite oxides: AZr(0.875)D(0.125)O3, where A is Ba or Sr and the dopant D is Y or Al. The high centrality region near the dopant is wider in the SrZrO3 systems than the BaZrO3 systems. In the aluminum-doped...