Synthesis and characterization of 4-[2(3-acetylphenyl) diazenyl]-3,5-dimethylphenol for heterojunction photodiode applications

Synthesis of azo dye, 4-[2(3-acetylphenyl) diazenyl]-3,5-dimethylphenol (ADD), is presented. The structural, linear optical and non-linear optical properties of ADD are studied together with the Ag/ADD/p-Si/Al heterojunction photodiode characteristics. The synthetic ADD is examined by using both Fourier transform infrared spectroscopy and nuclear magnetic resonance techniques. Its structure is also investigated using both X-ray diffraction and scanning electron microscopy techniques. Based on the spectrophotometric measurements of ADD thin film, several linear-optical parameters are calculated from the absorption spectra. The single-oscillator model is used to explain the dispersion parameters of ADD thin films. Semi-empirical relations are used to calculate the non-linear optical parameters from the linear optical parameters. The good optical properties of ADD thin films qualify ADD to be used in optoelectronic applications. So, Ag/ADD/p-Si/Al heterojunction photodiode is fabricated and its electrical properties are studied. Moreover, the Ag/ADD/p-Si/Al photodiode parameters (sensitivity, resistivity and detectivity) show good response to different illumination intensities.