guest ::
| Home > Publications database > Preparation of micro- and nanocrystalline CdSe and CdS thin films suitable for sensor applications |
| Home > Publications database > Preparation of micro- and nanocrystalline CdSe and CdS thin films suitable for sensor applications |
| Journal Article | PreJuSER-57069 |
; ; ; ;
2006
INOE & INFM
Bucharest
This record in other databases: 
Abstract: Thin films of CdS (30-200 nm) and CdSe (10-100 nm) are prepared by physical vapour deposition using one-step (for CdS and CdSe) or step-by-step (for CdSe only) approach. Atomic force microscopy measurements reveal a grain size decrease with decreasing layer thickness. The effect is strongest in the step-by-step CdSe layers. Raman scattering measurements show an anticipated gradual increase of the scattered light from CdS layers with thickness and a non-monotonous change in the CdSe group, the intensity is strongest for the '50 nm' 'step-by-step' CdSe layer. This observation is ascribed to a size-induced increase of the optical band gap of a part of the microcrystals whose estimated size is similar to 8 nm. Room temperature investigations of the effect of exposure to a set of vapours (water, ethanol, ammonia, acetone, iodine) on the dc dark and steady state photoconductivity of CdS layers show a reasonable response of all US layers to water vapour. CdSe layers are rather insensitive with the exception of the '50 nm' layer, as the 'step-by-step' layer shows the best sensitivity to all vapours. The observed good gas-sensitivity of the 'step-by-step' CdSe layers is ascribed to a much greater integral interface area between nanocrystals and indicates that 'step-by-step' deposition of CdSe layers is quite promising for gas-sensor applications.
Keyword(s): J ; thin films of CdS and CdSe (auto) ; physical vapour deposition (auto) ; atomic force microscopy (auto) ; dark and photoconductivity (auto) ; gas sensitivity (auto)
|
The record appears in these collections: |