Abstract: Disclosed is a method for fabricating a white LED which comprises, as a single active layer, an InGaN thin film which enables emission of white light. The InGaN thin film is constructed by taking advantage of the spinodal decomposition of the ternary compound and rapid thermal annealing. When growing the InGaN thin film on an n-type GaN formed on a sappier substrate under a growth condition, the thin film undergoes spinodal decomposition into two phases which show photoluminescence of a wavelength range from violet to blue and from green to blue, respectively, after which the surface of the thin film is thermally stabilized by rapid thermal annealing and the photoluminescence of the In-deficient phase is improved, so as to give intensive white photoluminescence to the InGaN single active layer. The LED which recruits such a single active InGaN thin film is superb in light emission efficiency and can be fabricated in a significantly reduced process steps.