Facilely Scalable Copper Telluride Photodetectors with On-Chip Spectral Selectivity Enabled by Laser-Direct-Written Gratings

Broadband ultraviolet-to-visible photodetection is of great importance for next-generation optoelectronic applications, yet the scalable integration of emerging high-performance materials with on-chip spectral-selectivity control remains a challenge. Here, we report a facile and scalable strategy for fabricating large-area copper telluride photodetectors, an underexplored transition-metal telluride, through vacuum thermal evaporation, followed by chemical vapor tellurization. The devices exhibit an outstanding broadband photoresponse across the UV-visible range, delivering responsivities of 210 mA/W at 365 nm and 200 mA/W at 465 nm. Optoelectronic characterizations confirm p-type conductivity and pronounced photogating effects, supported by a direct bandgap of 2.6 eV. Moreover, by integrating femtosecond laser-direct-written gratings with tunable periodicities, we actively engineer the spectral absorption profile, generating resonance peaks between 616 and 640 nm and enhancing absorption below 700 nm by more than 2-fold compared to planar films. This combination of scalable fabrication and on-demand spectral control establishes copper telluride as a promising material for programmable microstructured optoelectronics.