• Oxide-based programmable diodes with TiN/HfO2/Si/Al structure exhibit stable diode-like I-V characteristics in low-resistance state.
• Conduction and rectification are controlled by the interface between the oxygen vacancy filament and the semiconductor electrode.
• First-principle simulations reveal the local density of states and band bending, explaining the transport mechanisms.
• Electron transport is dominated by Poole-Frenkel emission under forward bias and reverse Schottky-diode behavior under negative bias.