Mixed phase thin films consisting of hydrogenated amorphous silicon (a-Si:H) in which germanium nanocrystals (nc-Ge) are embedded have been synthesized using a dual-chamber codeposition system. Raman spectroscopy and x-ray diffraction measurements confirm the presence of 4-4.5 nm diameter nc-Ge homogenously embedded within the a-Si:H matrix. The conductivity and thermopower are studied as the germanium crystal fraction XGe is systematically increased. For XGe < 10%, the thermopower is n-type (as in undoped a-Si:H) while for XGe > 25% p-type transport is observed. For films with 10 < XGe < 25% the thermopower shifts from p-type to n-type as the temperature is increased. This transition is faster than expected from a standard two-channel model for charge transport.
|Original language||English (US)|
|Title of host publication||Film Silicon Science and Technology|
|Number of pages||6|
|State||Published - 2013|
|Event||2013 MRS Spring Meeting - San Francisco, CA, United States|
Duration: Apr 1 2013 → Apr 5 2013
|Name||Materials Research Society Symposium Proceedings|
|Other||2013 MRS Spring Meeting|
|City||San Francisco, CA|
|Period||4/1/13 → 4/5/13|
Copyright 2013 Elsevier B.V., All rights reserved.