Volume 4 Issue 2
Authors: R. P. Razzoli; R. C. Michelini
Abstract: The ecology globalisation is defy, requiring defining strict technical targets, once aming at sustainable growth goals. The engineer’s activity is a central reference in the challenge, with a series of innovative opportunities, which include the ‹product-service› delivery, the ‹sustainable corporation› institute, the ‹lifecycle conformance certification› account and the other specific operation context details. These supply essential tools and techniques permitting the project management accomplishment.
Keywords: Eco-Project; Lifecycle Management; Service/Recovery Liability; Extended/Virtual Enterprise
Authors: A Watts; A Waheed; G. R.Mitchell; Key Server; S. K.Chakarvarti
Abstract: The electrical properties of nanocrystalline CdTe type II quantum dots based hetero structures deposited on conductive glass were investigated. They present interesting peculiarities. Low frequency (20 Hz ≤ f ≤ 200 kHz) dielectric properties of type II CdTe quantum dots blended with single walled carbon nanotubes (SWNTs, polyglycol functionalized) were investigated at room temperature. Negative capacitance was observed at low frequencies under forward DC biases. This phenomenon was found to result from the combinational contributions from the Maxwell-Wagner interfacial relaxation and the dipolar relaxation related to de-trapped carriers which give rise to inductive effect under an applied electric field. By using frequency dependent capacitance spectroscopy, the tunnelling effects of holes and electrons were investigated. In capacitance curves measured at low frequency, peaks were observed; these peaks could be attributed to the resonant tunnelling of charge carries into discrete energy levels of nanocrystalline CdTe and exhibit quantum confinement and Coulomb blockade effects. A clear (positive/negative) shift in capacitance-voltage(C-V) and conductance-voltage (G-V) suggests (electron/hole) trapping in nanocrystalline quantum dots.
Keywords: Hetero Structures; Single Walled Carbon Nanotubes; Negative Capacitance; Tunnelling Effects; Nanocrystalline Quantum Dots; Quantum Confinement; Coulomb Blockade Effects