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Hot carrier generation in silicon (Si) quantum dots (QDs) is studied with power dependent continuous wave photoluminescence (CWPL) spectroscopy. By taking sub-band gap absorption into account, a modified Maxwell-Boltzmann-form equation was employed to achieve accurate theoretical fitting to the CWPL spectra of the Si QDs. As a fitting parameter, the excited carrier temperature was calculated. A steady-state carrier population was revealed with a temperature 500 K above room temperature under illumination equivalent to one standard sun (100 mW/cm2). In addition, sice the carrier temperature increased with the power of illumination, a state filling effect is proposed as a reasonable cause for the elevated carrier temperature by comparative study of the CWPL spectra of Si QDs with three different sizes. These Si QDs show great potential for one of the steps towards a practical hot carrier solar cell (HCSC) device as high carrier temperatures can be achieved by state filling under mild illumination.
Bibliographical noteFunding Information:
This Program has been supported by the Australian Government through the Australian Renewable Energy Agency (ARENA) . Responsibility for the views, information or advice expressed herein is not accepted by the Australian Government. Thanks are also given to the Electron Microscope Unit of UNSW for TEM imaging support. In addition, U.K. and R.J.A. were supported by the UMN MRSEC Program of the National Science Foundation under Award Numbers DMR-0819885 and DMR-1420013 .
© 2015 Elsevier B.V. All right sreserved.
- Hot carrier solar cell
- Silicon quantum dots
- State filling
How much support was provided by MRSEC?
Reporting period for MRSEC
- Period 2