NOVELTY - The method for fabricating an optoelectronic device (1), comprises preparing a substrate (10), forming a multi-layer structure (12) on the substrate and forming a passivation layer (14) overlaying the multi-layer structure through an atomic layer deposition based process. The atomic layer deposition based process is a plasma-enhanced atomic layer deposition process and a plasma-assisted atomic layer deposition process. The passivation layer is formed at a processing temperature from room temperature of 600 degrees C. The passivation layer is further annealed at 100-1200 degrees C.    USE - The method is useful for fabricating an optoelectronic device. Uses include but are not limited to an organic light-emitting diode, an organic solar cell, an inorganic light emitting diode, an inorganic solar cell, a photo-detector and a laser diode (claimed).    ADVANTAGE - The method ensures the fabrication of optoelectronic device with high light emission efficiency and optoelectronic conversion efficiency.    DETAILED DESCRIPTION - The method for fabricating an optoelectronic device (1), comprises preparing a substrate (10), forming a multi-layer structure (12) on the substrate and forming a passivation layer (14) overlaying the multi-layer structure through an atomic layer deposition based process. The atomic layer deposition based process is a plasma-enhanced atomic layer deposition process and a plasma-assisted atomic layer deposition process. The passivation layer is formed at a processing temperature from room temperature of 600 degrees C. The passivation layer is further annealed at 100-1200 degrees C. The multi-layer structure has a PN-junction, a hetero-junction, a quantum well, a quantum wire, a quantum dot, a superlattice, a nanorod, a nanotube, a nanowire and a nanoparticle. An INDEPENDENT CLAIM is included for an optoelectronic device.    DESCRIPTION OF DRAWING(S) - The figure shows a fabrication method for optoelectronic device.    Optoelectronic device (1)    Substrate (10)    Multi-layer structure (12)    Passivation layer (14)    Carrier gas. (22)