Single oscillator model assessments and dielectric loss of non-crystalline brilliant green films, and characterization of brilliant green/p-Si photodetectors

Herein, spin-coated brilliant green films (from 95 to 237 nm) were characterized by an X-ray diffractometer (XRD). The extracted cell parameters of the analyzed monoclinic unit cell are a = 14.9650 Ǻ, b = 11.7708 Ǻ, c = 10.6658 Ǻ, α=90.00 Ǻ, β=134.76 Ǻ and γ=90.00 Ǻ, and space group P2. The extracted characteristic XPS peaks for brilliant green thin films at 283.82, 531.49, 398.44 and 168 eV are assigned to C 1s, O 1s, N1 s and S 2p, respectively. All the fabricated brilliant green films exhibit noncrystalline nature with indirect bandgaps. The recorded transmittance and reflectance are used to calculate the absorption coefficient. The refractive index of the brilliant green thin films is estimated by mathematical relations, depending on the extracted optical energy gap. In the non-absorbing region, the absorption edges are overlapped for all films at >1600 nm. The rate of optical energy dissipation revealed two triggering peaks in the visible region at 1.85 and 2.87 eV and 4.1 and 5.3 eV in the ultraviolet region with a higher absorption coefficient. The Cauchy and Sellimeier models analyzed and simulated observed dispersion data. The estimated values of the ideality factor, =3.41, the reverse saturation current, I_o=1.06×10⁻⁷A and =0.64 eV. The junction resistance, R_j, demonstrated reasonable rectification with low series resistance, R_s =795 Ω, and shunt resistance, R_sh =0.21 MΩ. The photodetector parameters of the brilliant green/p-Si interfaces are characterized, such as the SNR and LDR ratios, and show a linear, stable response with the photon energy ranging from 7 to 32 mW/cm². The evaluated detectivity has values of order 10¹¹ Jones with no detect value distortion.