Preparation of a nanostructured CdTe@CdS core–shell/Si photodetector by two-step laser ablation in liquid

In this study, CdTe@CdS core–shell nanoparticles (NPs) were synthesized by pulsed laser ablation in distilled water. X-ray diffraction results showed a crystalline core/shell type. UV–Vis measurements revealed that the optical band gap of CdTe@CdS NPs was 2.25 eV. Energy-dispersive X-ray mapping confirmed the formation of the CdTe@CdS core/shell. Transmission electron microscope studies revealed that the core size (CdTe) is 16 nm, and the shell thickness (CdS) is around 3 nm. The photoluminescence (PL) spectrum confirms the emission of a strong and broad peak at 506 nm. The current characteristics of the n-CdTe@CdS/p-Si heterojunction exhibited rectifying behavior with an ideality factor of 4.3. The spectral operating region of the fabricated photodetector ranged from visible to near-infrared, with a maximum responsivity of 0.901 A/W at 810 nm. The specific detectivity and external quantum efficiency of CdTe@CdS/Si were 4.5 × 10 11 Jones and 1.1 × 10 2 %, respectively, at a bias voltage of − 7.5 V.