Fabrication of CdSe/Si nanostructure for self-powered visible light photodetector

Self-powered visible light photodetector based nanostructured CdSe/Si geometry was fabricated using pulsed laser deposition (PLD). Herein, a detailed microstructural investigation was demonstrated in conjunction with the overall device photoresponsive performance. Particularly, an average particle diameter of 66.62 $\mathrm{nm}$ along optical band gap of 2.25 $\mathrm{eV}$ were attained. This was, subsequently, perceived in the fabricated device spectral response performance during which photocurrent ($I_{\mathrm{ph}}$) of 47 µA was attained under incident light of 575 $\mathrm{nm}$ and 6 $\mathrm{mW}/{\mathrm{cm}}^2$, the nearest incident wavelength to the obtained optical band gap. At the reported incident light features, the proposed arrangement exhibited responsivity ($R_{\lambda }$) of 7.85 $\mathrm{mA}/W$ with light to dark current ratio ($I_{\mathrm{ph}}/I_D$) of 998 %, respectively. Herein, the incident power variation suggested a linear increment ($R^2\approx$ 0.94) in both $I_{\mathrm{ph}}$ and $I_{\mathrm{ph}}/I_D$ profiles, with values of 71 µA and 1501 %, respectively, at 575 $\mathrm{nm}$ and 26 $\mathrm{mW}/{\mathrm{cm}}^2$. The fabricated device exhibited a pronounced time-resolved feature with rise/fall periods of 0.31 and 0.34 sec., while the power dependance based time-resolved behavior indicated a linear correlation between the stated factors with $R^2$ value of 0.924, both of which were carried out at 0 bias voltage. The dual-singularity evidenced the self-powered feature of the proposed photodetector, where zero external potential is required.