Photosensitive activity of fabricated core-shell composite nanostructured p-CuO@CuS/n-Si diode for photodetection applications

Graphical abstract
Highlights • Novel high-performance p-CuO@CuS/n-Si photodetectors have been facilely fabricated for the first time. • Structural and vibrational studied confirm the synthesis of fabrication of CuO@CuS nanocomposite system. • Core-shell structure like morphology was approved by FESEM & HRTEM analyses. • The high photosensitivity (Ps) of ∼ 7.76 × 104 % and photoresponsivity (R) ∼ 798.61 mA/W was observed for the fabricated photodetector. • The high specific detectivity (D*) of 8.19 × 1011 Jones and external quantum efficiency (QE) of ∼ 309.66 %, was observed for the fabricated photodetector.
Development of photo detectors based on different semiconducting materials with high performance has been in progress in recent past, however, there is a lot of difficulties in developing the more effective photo detectors-based devices with high responsivity, detectivity and quantum efficiency. Hence, we have synthesized pure CuS and CuO@CuS core-shell heterostructure based photo detectors with high performance by simple and cost-effective two-step chemical co-precipitation method. The phase purity of CuS and CuO@CuS composite was observed by XRD analysis and the result were verified with Raman spectroscopy studies. Sphere like morphology of pure CuS and core-shell structure formation of CuO@CuS are observed with scanning and transmission electron microscopes. The presence of expected elements has been confirmed with EDX elemental mapping. Light harvesting photodiodes were fabricated by using n-type silicon substrate through drop cost method. Photo sensitive parameters of fabricated diodes were analyzed by I–V characteristics. The p-CuO@CuS (1:1)/n-Si diode owned a maximum photosensitivity (Ps) ∼ 7.76 × 104 %, photoresponsivity (R) ∼ 798.61 mA/W, external quantum efficiency (EQE)∼309.66 % and specific detectivity (D*) ∼ 8.19 × 1011 Jones when compared to p-CuS/n-Si diode. The obtained results revealed that the core/shell heterostructure of CuO@CuS is the most appropriate for photo detection.