Study on the luminescence properties of n-ZnO/p-Si hetero-junction diode grown by MOCVD

n-ZnO/p-Si hetero-junction light emitting diodes were fabricated using a metal organic chemical vapour deposition (MOCVD) technique. Room temperature (RT) photoluminescence (PL) spectrum showed an intense main peak at 377 nm and a weak deep-level emission. The I-V characteristics of the n-ZnO/p-Si hetero-junction showed rectifying diode behaviour at different temperatures. At a low bias voltage, typical values of the ideality factors were determined to be 2.84 at 77 K and 1.94 at 300 K, indicating that the junction had good diode characteristics. RT electroluminescence (EL) was detected under forward bias, which covered a broad visible range (400-600 nm) corresponding to defect-related emission. The remarkable difference between the PL and EL spectra was ascribed to their different excitation and recombination processes. Infrared EL emission at Si band gap energy based on the n-ZnO/p-Si hetero-junction structure was also detected