Using the diffusivity discrepancy between Al and N in the SnO2phase, N-doped n+and Al-doped p+degenerate regions were created at the interface by annealing an AlN/SnO2bilayer. Current-voltage (I-V) characteristics of the p+-AlN:SnO2/n+-SnO2junction indicate distinct tunnel diode characteristics, such as the tunneling mode, negative differential resistance, and turn-on mode. The overall transmittance of the p-AlN:SnO2/n-SnO2tunnel diode is higher than 80% in the visible region. In a certain wavelength region, the transmittance of the p-AlN:SnO2/n-SnO2tunnel diode is even higher than 90%. This shows that a transparent p-AlN:SnO2/n-SnO2tunnel diode has great potential for use in a broad range of invisible electronics.