Characterization of Responsivity and Quantum Efficiency of TiO2– Based Photodetectors Doped with Ag Nanoparticles

There is a motivation to reduce the thickness of photodetectore to improve the efficiency of extracting excuted carrier. However, reducing the thickness of thin film also reduces the amount of light absorbed. To alleviate this problem we can use light trapping. Ag Nanoparticles with specific diameters are exposed to improve optical characteristics of TiO2-based photodetectors. Optical properties of photodetectors depend on optical properties of nanoparticles. There for photodetectore application we need to identify which of these properties(scattering, absorption) are beneficial and then design suitable nanoparticle to maximize these effect while minimizing unwanted optical properties. Nanoparticles diameter is usually between 5-100nm. If the diameter of nanoparticles is about more than 100nm, light will not be absorbed efficiently, and when it is smaller than 5nm, charge transition through channels fades and scattering is increased. Effect of nanoparticles on absorption coefficient, quantum efficiency, and responsivity of photodetectors based on TiO2 are discussed in this paper. Keywords—Nanoparticle(NP); Responsivity(R); Absorption coefficient; Quantum Efficiency(QE)