High-Performance Self-Powered Photodetector Enabled by Te-Doped GeH Nanostructures Engineering

Highlights What are the main findings? A facile chemical strategy was developed for the synthesis of two-dimensional Te-doped GeH nanostructures with atomic-level precision and structural integrity. The Te-GeH-based photoelectrochemical (PEC) photodetectors exhibit high responsivity (708.5 mu A/W) and ultrafast response speeds (92 ms rise/526 ms decay) under zero-bias conditions, demonstrating excellent broadband photoresponse. What is the implication of the main finding? The introduction of Te atoms enables effective modulation of the electronic structure in the GeH system. Owing to the comparable atomic radius between Te and Ge, efficient doping is achieved without disrupting the host lattice. In addition, the high electronegativity of Te induces electron redistribution and facilitates the formation of a built-in electric field, thereby optimizing charge separation and transport behavior. This approach provides a novel pathway for the functional design of Zintl-phase-derived two-dimensional materials, with broad implications for advanced optoelectronic applications. This doping strategy significantly enhances the photoelectrochemical performance of GeH-based photodetectors and enables the scalable fabrication of 2D nanomaterials with tunable optoelectronic properties. The resulting Te-GeH nanostructures offer improved carrier dynamics and reduced recombination, serving as a promising material platform for next-generation self-powered broadband photodetectors.Highlights What are the main findings? A facile chemical strategy was developed for the synthesis of two-dimensional Te-doped GeH nanostructures with atomic-level precision and structural integrity. The Te-GeH-based photoelectrochemical (PEC) photodetectors exhibit high responsivity (708.5 mu A/W) and ultrafast response speeds (92 ms rise/526 ms decay) under zero-bias conditions, demonstrating excellent broadband photoresponse. What is the implication of the main finding? The introduction of Te atoms enables effective modulation of the electronic structure in the GeH system. Owing to the comparable atomic radius between Te and Ge, efficient doping is achieved without disrupting the host lattice. In addition, the high electronegativity of Te induces electron redistribution and facilitates the formation of a built-in electric field, thereby optimizing charge separation and transport behavior. This approach provides a novel pathway for the functional design of Zintl-phase-derived two-dimensional materials, with broad implications for advanced optoelectronic applications. This doping strategy significantly enhances the photoelectrochemical performance of GeH-based photodetectors and enables the scalable fabrication of 2D nanomaterials with tunable optoelectronic properties. The resulting Te-GeH nanostructures offer improved carrier dynamics and reduced recombination, serving as a promising material platform for next-generation self-powered broadband photodetectors.Abstract Two-dimensional (2D) Xenes, including graphene where X represents C, Si, Ge, and Te, represent a groundbreaking class of materials renowned for their extraordinary electrical transport properties, robust photoresponse, and Quantum Spin Hall effects. With the growing interest in 2D materials, research on germanene-based systems remains relatively underexplored despite their potential for tailored optoelectronic functionalities. Herein, we demonstrate a facile and rapid chemical synthesis of tellurium-doped germanene hydride (Te-GeH) nanostructures (NSs), achieving precise atomic-scale control. The 2D Te-GeH NSs exhibit a broadband optical absorption spanning ultraviolet (UV) to visible light (VIS), which is a critical feature for multifunctional photodetection. Leveraging this property, we engineer photoelectrochemical (PEC) photodetectors via a simple drop-casting technique. The devices deliver excellent performance, including a high responsivity of 708.5 mu A/W, ultrafast response speeds (92 ms rise, 526 ms decay), and a wide operational bandwidth. Remarkably, the detectors operate efficiently at zero-bias voltage, outperforming most existing 2D-material-based PEC systems, and function as self-powered broadband photodetectors. This work not only advances the understanding of germanene derivatives but also unlocks their potential for next-generation optoelectronics, such as energy-efficient sensors and adaptive optical networks.