Fabrication and characterization of a visible photodetector based on a germanium/n-type silicon heterojunction using thermal evaporation deposition

This work reveals a distinctive Ge /Si photo-detector shape as a function of Ge window layer, using cost-effective thermal evaporation technique. X-ray diffraction (XRD) investigation revealed the presence of a good crystalline layer a closed-oriented crystalline structure, whereas nanoparticle sizes of 80 nm were measured employing field emission scanning electron microscopy (FE-SEM). The Raman spectroscopic investigation of Ge film the figure shows three separate peaks, In particulars are corresponded to Ge phase, E(TO + LO), A1(TO), E(TO)respectively. From UV-visible measures, the attained optical band gap for Ge layer was found to be 2.8 eV. Show FESEM of the Ge layer, the presence of a compact surface along a continuous nanoparticles formation. In especially, the average diameter of nanoparticles in the layer ranged from 45 nm to 66 nm, and the image shows cross section that the thickness of the Ge sheet is about 746 nm. At the same time, the manufactured devices exhibited an organized figure of merit as an index of wavelength at a very low bias voltage. The optimal device at 405 nm had responsivity of 4.805 µA/mW and detectivity of 1.35 × 1017 Jones. It also had a quantum efficiency of 14.711 at 100 mW/cm², but this was found to decrease at lower and higher wavelengths. The demonstrated device had response time and recovery time of 0.34 and 0.32 s at zero bias voltage respectively, demonstrating the suggested systems self-powered feature. The suggested shape offers a cost-effective solution for optoelectronic systems, while still being durable and stable.