Monolithic Integration of Rare-Earth-Doped Tellurite Thin Films with Silicon for Dual-Function Optical/Temperature Detectors in Single-Chip Heterojunction Devices

For next-generation applications, recent developments in sensor fabrication technologies and innovative materials have rendered improved temporal response and spectral detection capabilities feasible. This work demonstrates a dual-mode sensor for simultaneous light and temperature detection. Vacuum thermal evaporation was used to deposit nanostructured polycrystalline TeO2–Li2O–ZnO–Nb2O5–Dy2O3 (TLZND) thin films (∼32 nm crystallites) on monolithic substrates. Field-emission scanning electron microscopy revealed surface morphology and roughness, while Fourier transform infrared spectroscopy described postevaporation molecular structural changes. Optical characteristics, such as energy gap and dispersion parameters, were determined using UV–vis–near-IR spectroscopy. Dark direct-current conductivity showed three different activation energy regions, increasing from 6.33 × 10–5 to 2.14 × 10–3 Ω–1 cm–1. Three sensitivity regions with different linearities were shown by silicon-integrated TLZND heterojunctions between 303 and 473 K. Effective dual-mode sensing capability was confirmed by the sensor’s fast response to halogen and multiwavelength laser radiation, which resulted in optimal infrared performance: 7.44 A/W responsivity, 6.82 × 1010 Jones detectivity, and 40 ms response time.