Electric and optoelectronic balances of silicon photodetectors coupled with colloid carbon nanodots

We present the efficient ultraviolet photodetectors made with the incorporation of colloid carbon nanodot (CCND) layers with silicon substrates. By investigating the morphologies, microstructure, light absorption and carrier dynamics, the control over CCND thickness is envisioned for the improvement of photosensing characteristics. We find that 35-nm thick CCNDs coupled with Si can reach remarkable sensing responsivity of 15.9 A/W and detectivity of 2.94 × 10¹⁴ Jones under detecting lights with wavelength of 352 nm. The underlying mechanism is interpreted by the synergetic contributions from reduced dynamic dark currents and efficient charge separation from CCND/Si heterojunction.