18,181 research outputs found
Anomaly of Film Porosity Dependence on Deposition Rate
This Letter reports an anomaly of film porosity dependence on deposition rate
during physical vapor deposition - the porosity increases as deposition rate
decreases. Using glancing angle deposition of Cu on SiO2 substrate, the authors
show that the Cu film consists of well separated nanorods when the deposition
rate is 1 nm/second, and that the Cu films consists of a more uniform (or lower
porosity) film when the deposition rate is 6 nm/second; all other deposition
conditions remain the same. This anomaly is the result of interplay among
substrate non-wetting, density of Cu nuclei on the substrate, and the minimum
diameter of nanorods
Multiquantum well structure with an average electron mobility of 4.0×10^6 cm^2/V s
We report a modulation-doped multiquantum well structure which suppresses the usual ambient light effect associated with modulation doping. Ten GaAs quantum wells 300-Å wide are symmetrically modulation doped using Si δ doping at the center of 3600-Å-wide Al0.1Ga0.9As barriers. The low field mobility of each well is 4.0×10^6 cm/V s at a density of 6.4×10^10 cm^−2 measured at 0.3 K either in the dark, or during, or after, exposure to light. This mobility is an order of magnitude improvement over previous work on multiwells
- …