To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
In this work, we present the optoelectronic characterization of pure tungsten oxide nanoparticle networks synthesized and self-assembled by flame spray pyrolysis. Current-voltage measurements performed in dark conditions indicate the presence of trapping and de-trapping phenomena from defects inside the energy gap. The presence of defects is confirmed by the time evolution of the photocurrent, measured under monochromatic radiation at 420 nm. After illuminating the WO3 films with light, the current increases exponentially with a time constant independent on the applied voltage. This behavior is ascribed to the presence of defects lying at 1.1 eV below the conduction band of WO3 (bandgap of ca. 2.9 eV). When the illumination is terminated, the photocurrent shows an exponential decrease, once again independently on the applied voltage. The defect level corresponding to this relaxation process corresponds to 0.92eV below the conduction band.
In this paper, we present a compact lab-on-chip system suited for label-free DNA analysis. The system can be fabricated on a conventional microscope glass slide using thin-film and thick-film technologies. It integrates a heating chamber, an electrowetting-based droplet handling system and a hydrogenated amorphous silicon (a-Si:H) photosensor array for DNA detection. At this stage of research we have designed and tested the individual functional units. The heating chamber incorporates a thin metal film heater optimized for uniform temperature distribution on a 1cm2 area. A forward-biased a-Si:H p-i-n junction is used for temperature monitoring, achieving a linear temperature dependence with -3.3 mV/K sensitivity. The droplet-handling unit, relying on the electrowetting method, is designed to move the sample from the heating chamber to the sensor array. The unit includes a set of metal pads beneath a layer of PDMS that provides both the electric insulation of the electrodes and the hydrophobic surface needed by the electrowetting technique. The UV sensor array allows measuring the DNA absorbance variation at 254nm related to the hybridization between probe-molecules contained in the sample and reference target molecules immobilized on the sensor surface. A preliminary test to detect the hybridization between a 25-mer single-stranded oligonucleotides and denaturated pBR 322 4162-mer single-stranded oligonucleotides has been carried out successfully.
In this work we report on the effect of current-induced degradation and annealing on p-i-n amorphous silicon solar cells. Current-voltage curves and capacitance measurements under forward bias have been used to monitor the current-induced changes as a function of time. We found that the recovery rate increases with the annealing current, while the stabilized value of efficiency decreases. Comparison of short circuit current and capacitance evolution suggests that defect kinetics in the electronic gap occurs in a different way during degradation and annealing. This behavior can be modeled assuming a faster annealing of defects closest to the extended band and a slower annealing of mid-gap defects.
Email your librarian or administrator to recommend adding this to your organisation's collection.