Through computing and analysing reflection losses of various antireflective coatings consisting of SiO 2,Si 3N 4 or Al 2O 3 on the surface of Si optoelectric devices,the optimum data can be obtained.It has been found that SiO 2 layer of 95 nm will be optimum if single layer is used.Further improvements can be achieved by using a combination of 40 nm Si 3N 4 and 40 nm SiO 2 or 45 nm Al 3O 3 and 45 nm SiO 2.Reflection loss would be vibrational if more than two layers are used,therefore this structure is not preferred.