Preparation method of copper nitride powder

A preparation method of a copper nitride powder, comprises the steps of: constructing a sacrificial layer disposed on a support layer, for example a silica sacrificial layer on a silicon wafer or a photoresist sacrificial layer on glass; growing a copper nitride film on the sacrificial layer; changing the external conditions to modify the sacrificial layer and obtain a separate copper nitride film; and cleaning, drying, grinding, and sieving the separate film to obtain the copper nitride powder. Changing the external conditions, e.g. by soaking in a liquid, heating or cooling, can change the humidity, pH or temperature to cause the sacrificial layer to lose the original connectivity thereof. Suitably, the sacrificial layer is an oxide or an organic viscous substance, and the external conditions are changed by etching or losing the viscous substance. The sacrificial layer may be constructed by plasma-enhanced chemical vapour deposition (PECVD), oxidation reaction or spin coating. The separate film may be cleaned by rinsing with deionised water and an organic solvent 3-5 times successively and repeatedly, and finally rinsing with deionised water. The cleaned film may be dried under vacuum or in a nitrogen atmosphere for 3-10 hours at a temperature of 50-80°C.