Pixelated-LED chips and related methods are disclosed. A pixelated-LED chip includes an active layer with independently electrically accessible active layer portions arranged on or over a light-transmissive substrate. The active layer portions are configured to illuminate different light-transmissive substrate portions to form pixels. Various enhancements may beneficially provide increased contrast (i.e., reduced cross-talk between pixels) and/or promote inter-pixel illumination homogeneity, without unduly restricting light utilization efficiency. In some aspects, an underfill material with improved surface coverage is provided between adjacent pixels of a pixelated-LED chip. The underfill material may be arranged to cover all lateral surfaces between the adjacent pixels. In some aspects, discontinuous substrate portions are formed before application of underfill materials. In some aspects, a wetting layer is provided to improve wicking or flow of underfill materials during various fabrication steps. Other technical benefits may additionally or alternatively be achieved.