Electron Selective Passivation Contact of Hydrogenated Titanium Nitride for Crystalline Silicon Solar Cells

Dopant‐free electron‐selective contact materials with hydrogen passivation are crucial for electronic extraction applications for crystalline silicon (c‐Si) cells. However, research on these materials, particularly transition metal nitrides, is limited. In this work, we investigate a titanium nitride (TiN)/SiO x stack placed between c‐Si and metal electrode, examining how hydrogen passivate affect the interfacial contacts. Three methods were investigated: (1) using Ar/H 2 (95%/5%) as the working gas during TiN deposition; (2) pure Ar during TiN deposition followed by postannealing at 250°C for 30 min; and (3) Ar/H 2 during deposition, followed by postannealing. A control group without hydrogenation is also included. The best performance, with a contact resistivity of 1.48 mΩ·cm 2 and an open‐circuit voltage of 674.4 mV, result in a champion power conversion efficiency of 22.4% as the dopant‐free electron‐selective contact material. This work highlights the sensitivity of transition metal nitrides, such as TiN, to hydrogenation under natural oxidizing conditions and emphasized the critical role of postannealing processes and material compatibility.