A Lead Selenide Thin Film for Photovoltaic Application

Currently, the United States is highly dependent on fossil fuels for the majority of its energy needs. This problem has many negative consequences for our nation. In order for solar energy to be cost competitive with fossil fuels, the manufacturing and material costs must be reduced while the conversion efficiency is increased. Thin film lead selenide was investigated for photovoltaic application. If incorporated into a heterojunction solar cell, PbSe has the potential to reduce overall costs through the use of less material and a low cost, low temperature deposition technique, as well as the potential to increase conversion efficiency due to the potential of carrier multiplication in PbSe quantum dots.

P-type polycrystalline PbSe thin films have been fabricated by chemical bath deposition. The electrical properties of these PbSe thin films can be reproducibly controlled through variation of the deposition conditions. P-type PbSe thin films with hole densities varying from 4.28x10^17 to 1.91x10^19 cm^-3 have been achieved. The results suggest that PbSe thin films were also fabricated in which both electrons and holes contribute to conduction. High hole mobility for polycrystalline PbSe has been achieved. Additionally, proof of concept has been demonstrated for a heterojunction composed of p-type nanocrystalline PbSe and n-type monocrystalline Si. The heterojunction between the two highly doped semiconductors exhibits rectifying behavior, laying the foundation for future investigation of such a heterojunction.