Title :
Infrared photodiode based on colloidal PbSe nanocrystal quantum dots
Author :
Cui, Dehu ; Xu, Jian ; Xu, Sheng-Yong ; Paradee, Gary ; Lewis, Bradley A. ; Gerhold, Michael D.
Author_Institution :
Pennsylvania State Univ., University Park, PA
fDate :
7/1/2006 12:00:00 AM
Abstract :
We report in this paper our studies on the photoconductivity and photovoltaic effects of colloidal PbSe nanocrystal quantum dots (NQDs) which were embedded in conductive polymer matrices to form hybrid polymer/NQD infrared photodiodes. The generation of photocarriers in PbSe NQDs and their transport in NQD-polymer composites were described by a simplified band diagram picture of the device. Both photocurrent and photovoltage outputs were measured from the NQD-incorporated photodiode upon the illumination of near-infrared (NIR) light, whereas the net polymer-based devices do not exhibit any photoresponsivity. The intensity dependence of the photocurrent indicates the pseudomonomolecular recombination kinetics in the NQD-polymer composite. The measured photocurrent spectrum is consistent with the absorption characteristic of PbSe NQDs. Further enhancement of the photodiode efficiency can be achieved by engineering the nanocrystal surface to reduce the potential barriers due to the ligant capping molecules
Keywords :
IV-VI semiconductors; colloids; composite materials; lead compounds; nanostructured materials; photoconductivity; photodiodes; photovoltaic effects; polymers; semiconductor quantum dots; PbSe; band diagram; colloidal nanocrystal quantum dots; conductive polymer matrices; infrared detectors; infrared photodiodes; ligant capping molecules; nanocrystal quantum dots-polymer composites; nanocrystal surface; near-infrared light; photocarriers; photoconductivity; photocurrent; photovoltage; photovoltaic effects; polymer-based devices; potential barriers; pseudomonomolecular recombination kinetics; semiconductor materials; Absorption; Kinetic theory; Lighting; Nanocrystals; Photoconductivity; Photodiodes; Photovoltaic effects; Polymers; Quantum dots; Radiative recombination; Infrared detectors; photoconductivity; photodiode; photovoltaic effects; semiconductor materials;
Journal_Title :
Nanotechnology, IEEE Transactions on
DOI :
10.1109/TNANO.2006.877432