Integration of biocompatible Coomassie Brilliant Blue dye on silicon in organic/Inorganic heterojunction for photodetection applications

Abstract

Here, we introduce systematic investigations of structural, morphological, and optical properties of solution- processed coomassie brilliant blue, CBB, thin films for photodetection applications. First, the structural and morphological features of the spin-coated CBB thin films are investigated using XRD and FESEM microscopy and yielded a polycrystalline, nanostructured, and porous CBB film of crystallite size and RMS roughness ~31.95 nm and 10.65 nm, respectively. The UV–Vis–NIR spectrophotometric measurements of transmittance and reflectance elucidated the efficient absorption and light-harvesting of the UV and visible light range with estimated indirect energy gap and Urbach energy ~1.54 eV and 22.3 meV, respectively. Next, the dispersion behavior of the fabricated thin films is analyzed in the light of the single-oscillator model estimating the detail dispersion pa- rameters. Furthermore, the dielectric function, as well as the nonlinear optical parameters, is accurately esti- mated. Subsequently, the microelectronic parameters of the engineered rectifying Ag/CBB/p-Si/Al heterojunction such as ideality factor, barrier height, series, and shunt resistances are estimated at different temperatures. The charges dynamical mechanism and the interface states density profile are analyzed, and the thermionic emission model is confirmed to fit the low bias region with a modified Richardson constant of about 34.8A/cm2 K2 .After that, the photoresponse of the implemented organic/inorganic heterojunction is checked at different illumination intensities and showed a significant stable sensitivity with fast On-Off switching behavior. The fabricated heterojunction achieved good figures of merit such as responsivity, specific detectivity, linear dynamic range, and rise/fall time of about 4.289 mA/W, 2.07 × 109 Jones, 30.36 dB, and 61.6/82.5 ms, respectively. The good and stable responsive performance of the current Ag/CBB/p-Si/Al architecture may make it a potential candidate for photodetection applications