n-ZnO/p-4H-SiC diode: Structural, electrical, and photoresponse characteristics

Epitaxial n-type ZnO film has been grown, on a commercial 5 μm thick p-type 4H-SiC(00.1) Al doped epilayer, by atomic layer deposition. A full width at half maximum of the ZnO 00.2 diffraction peak rocking curve of 0.34° ± 0.02° has been measured. Diodes formed on the n-ZnO/p-4H-SiC heterostructure show rectifying behavior with a forward to reverse current ratio at the level of 109 at ±4 V, a leakage current density of ∼6 × 10−8 A/cm2, and a low ideality factor equal to 1.17 ± 0.04. In addition, the diodes exhibit selective photoresponse with a maximum at 367 nm, and with a current increase of ∼103 under illuminations with respect to the dark value, which makes such devices prospective candidates for ultraviolet light sensors.