Graphene Capped Silicon Nanocrystals for Optoelectronic Devices

Quantum confinement effect combined with surface states at the SiNCs/SiO_x interface has revealed efficient light emission under UV illumination. It’s a challenge when charged carriers are needed to be injected into the core for getting efficient luminescence for LED applications or photogenerated e-h pairs form the core of SiNCs are to be extracted for photovoltaic applications. This is because the SiNCs are embedded in insulating silicon oxide matrix that restricts injection or extraction of charge carriers from the core. We have encapsulated SiNCs by graphene layer, so that the optoelectronic property of the SiNCs is not suppressed and obtain additional electrical path through which electronic interaction can be possible. SiNCs and GO were procured and subjected for in-situ wet chemical technique, where RGO encapsulate each single SiNC through which charged carriers can be injected and extracted. Encapsulation of SiNCs by RGO also minimizes the thickness of the SiO_x shell without any significant change in optical properties. Respective signature characterizations viz. Raman, UV-Vis spectroscopy, TEM and PL have been carried out and the optoelctronic properties have been studied to confirm the potential application of the composite for optoelectronic devices.