Reporting their work in the journal Nanotechnology (24 195701), researchers from National Chiao Tung University, Taiwan, explain that the Si QD thin film formed using a GSRO ML structure offers improved PV properties compared with samples based on a [SiO2/SRO] ML structure thanks to enhanced optical absorption and carrier transport.

Also, since a Si QD thin film utilizing a heavily doped [SiO2/SRO] ML structure can exhibit better carrier transport properties than a generally doped one, the team believes that it is feasible to further improve the PV properties by employing a heavily doped GSRO ML structure.

Full details can be found in the journal Nanotechnology.

Further reading -

Silicon quantum dot/crystalline silicon solar cells (May 2008)
QD photodetector speeds up (Nov 2012)