Nanowires (NWs) have been extensively studied over the last few decades for both scientific interest and technological potential. Semiconductor NWs’ physical properties are profoundly dependent on their chemical composition and especially so on their dopant concentration, profiles and activity level. Controlling NWs axial and radial dopant profiles is, therefore, of utmost importance for NW-bas...

As the gate length of MOSFET devices shrinks down below 100 nm, the fluctuation of major devices parameter, namely, threshold voltage (VTH), subthreshold swing, drain current (ID) and subthreshold leakage current due to influences of processes variations becomes a serious problem. Random dopant fluctuation is one of the problems. In this work, we numerically examine the fluctuation effects of r...

The sensitive dependence of a semiconductor's electronic, optical and magnetic properties on dopants has provided an extensive range of tunable phenomena to explore and apply to devices. Recently it has become possible to move past the tunable properties of an ensemble of dopants to identify the effects of a solitary dopant on commercial device performance as well as locally on the fundamental ...

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...