Hydrothermally synthesised Gd2Te4O11 nanorods for broadband visible light photodetection and NLO applications.

Rare earth tellurium oxides belong to a wide bandgap group, which makes them prominent candidates for optoelectronic applications. Gadolinium tellurate (IV) (GTO) samples with varying concentration ratios of Gd and Te were synthesised through a hydrothermal method. All samples confirmed the Gd2Te4O11 structure with a monoclinic crystal system. Nanorods are observed in most samples, and EDX confirmed the presence of the constituent elements. The XPS study was carried out to obtain the chemical composition and oxidation states. Optical studies of materials showed band gap values lying between 4.1 eV and 4.3 eV. From the photoresponse study, it is clear that the performance of all GTO photodetector devices (PDs) is good. The nonlinear optical (NLO) study confirmed that the nonlinear refractive index dominated over two-photon absorption for all samples, with a maximum nonlinear refractive index of 3.305 × 10-5 cm2 W-1 and a nonlinear optical susceptibility of 38.811 × 10-4 (esu). All the samples showed a high figure of merit (FOM), with a maximum value of 195.789. This makes GTO samples suitable for all nonlinear optical devices and optical switching applications.