Thin films of lead sulfide alloyed with thorium and oxygen were deposited on GaAs substrates and processed to produce a photo-diode structure. Structural, optical and electrical characterizations indicate the presence of small nanoscale domains (NDs) that are characterized by dense packaging, high quality interfaces and a blue-shift of the energy bandgap toward the short wavelength infrared range of the spectrum. Photocurrent spectroscopy revealed a considerable photoconductivity that is correlated with excitation of carriers in the NDs of lead sulfide alloyed with thorium and oxygen. Furthermore, the appearance of a photovoltaic effect under near infrared illumination indicates a quasi-type II band alignment at the interface of the GaAs and the film of NDs.
Bibliographical noteFunding Information:
This joint research project has been supported by a grant from INNI (Israeli National Nanotechnology Initiative) under the FTA (Focal Technology Areas) program and by the Israel Science Foundation under Grant #156/2014. NA-V acknowledges the support of the Dr Ilana Levitan fellowship.
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- infrared photoconductivity
- lead sulfide nanostructures