MoS2 and H-terminated nanocrystalline diamond (H-NCD) heterostructures were investigated for enhanced gas sensing. Individual MoS2 and H-NCD films were synthesized and characterized (SEM, Raman, contact angle, GIWAXS). While MoS2 and H-NCD showed weak room-temperature gas responses, the MoS2/H-NCD heterostructure exhibited significantly improved sensitivity to both NO2 (0.157%·ppm⁻¹) and NH3 (0.188%·ppm⁻¹). This synergistic effect stems from a P-N junction formed between P-type H-NCD and N-type MoS2, modifying the space charge region (SCR) upon gas exposure. A gas interaction model incorporating chemisorption (MoS2) and surface transfer doping (H-NCD) was developed. Although the heterostructure lacked selectivity (increased resistance for both oxidizing and reducing gases), a combined MoS2/H-NCD and single MoS2 sensor chip is proposed for gas type and concentration determination. This work demonstrates a new class of miniature, low-power conductivity gas sensors with potential for portable and energy-harvesting applications, and the results attracted the attention of industry (new TACR has been initialized at FZU with 2 Czech industrial partners).
