Enhanced photoconductivity via photon down-conversion by incorporation of solution-processed 3C-SiC QDs on nanostructured black silicon

Colloidal quantum dots (CODs) have attracted attention towards the next-generation optoelectronic devices capable of tuning the bandgap to capture photons at the UV region which is the major impediment of silicon (Si) for optoelectronic applications. However, CODs convert higher-energy photons into lower-energies photons through spectral down-conversion to UV visible. This study describes the photoconductivity effects of colloidal 3C-SiC QDs onto the underlying black silicon (b-Si) for spectral down-conversion effect. The Si showed a remarkable decrease in broadband reflectance after being etched to b-Si via metal-assisted chemical etching (MACE) over a broad spectral wavelength range of 300–1100 nm. Incorporating QDs onto underlying b-Si enhanced the device responsivity from 0.034 A/W to 0.53 A/W with the formation of space charge through the down-conversion effect. Furthermore, the photovoltaic measurements demonstrate the superior performance of hybrid colloidal 3C-Si QDs/b-Si with a power conversion efficiency (PCE) of ∼7.28 % compared to b-Si without QDs (5.57 %) photovoltaic cells. Our research provides insight into the down-conversion effects of colloidal 3C-SiC QDs for photovoltaic and photodetector applications.