Growth and characterization of Ir3Se8 thin films via chemical vapor deposition for NIR photodetector and gas sensor applications

Platinum-group metal chalcogenides exhibit significant potential for electronic and optoelectronic applications due to their promising semiconducting properties. However, the growth of iridium chalcogenides remains underdeveloped, mainly due to challenges such as the limited availability of suitable precursors, difficulties in achieving precise stoichiometric control, and the complexity of their crystallization processes. In this work, we present the first successful synthesis of Ir₃Se₈ thin films via chemical vapor deposition (CVD) using a novel iridium precursor, tricarbonyl (1,2,3-η)-1,2,3-tri(tert-butyl)-cyclopropenyl iridium (TICP), with Se powder. The films were deposited at temperatures ranging from 300 to 500°C, and structural analysis revealed that 300°C is the optimal growth temperature for obtaining high-quality, stoichiometric Ir₃Se₈ films. Optical characterization of Ir₃Se₈ using UV-Vis-NIR spectroscopy determined the bandgap to be 0.67 eV, confirming its semiconducting nature. Additionally, metal-semiconductor-metal (MSM) devices fabricated with the synthesized Ir₃Se₈ films demonstrated stable near-infrared (NIR) photoresponse. Furthermore, gas sensor measurements exhibited a high response of 640% and a recovery rate of 97% for NO₂ detection at room temperature. This study provides a novel approach for the low-temperature synthesis of Ir₃Se₈ and highlights its potential in optoelectronic and gas sensing applications.