A pixelated-LED chip comprising: an active layer comprising a plurality of active layer portions (222-1, 222-2, 222-3); a plurality of substrate portions (342-1, 342-2, 342-3) supporting the plurality of active layer portions (222-1, 222-2, 222-3), wherein each substrate portion (342-1, 342-2, 342-3) comprises a light-transmissive material, a light injection surface, and a light extraction surface, wherein the light injection surface is arranged between the active layer and the light extraction surface; and a plurality of anode-cathode pairs (228, 229) deposited over, and in conductive electrical communication with, the plurality of active layer portions (222-1, 222-2, 222-3); wherein each active layer portion (222-1, 222-2, 222-3) of the plurality of active layer portions (222-1, 222-2, 222-3) comprises a different anode-cathode pair (228, 229) of the plurality of anode-cathode pairs (228, 229) and is configured to illuminate a different substrate portion (342-1, 342-2, 342-3) of the plurality of substrate portions (342-1, 342-2, 342-3) and transmit light through the light extraction surface of the substrate portion (342-1, 342-2, 342-3), such that the plurality of active layer portions (222-1, 222-2, 222-3) and the plurality of substrate portions (342-1, 342-2, 342-3) form a plurality of pixels (344a, 344b, 344c); characterised in that the light extraction surface of each substrate portion (342-1, 342-2, 342-3) comprises a light extraction surface recess between pixel sidewalls of the plurality of pixels (344a, 344b, 344c), the pixel sidewalls comprising sides of each substrate portion (342-1, 342-2, 342-2); and the pixelated-LED chip further comprises a reflective layer on the pixel sidewalls including sides of each substrate portion (342-1, 342-2, 342-3). an active layer comprising a plurality of active layer portions (222-1, 222-2, 222-3); a plurality of substrate portions (342-1, 342-2, 342-3) supporting the plurality of active layer portions (222-1, 222-2, 222-3), wherein each substrate portion (342-1, 342-2, 342-3) comprises a light-transmissive material, a light injection surface, and a light extraction surface, wherein the light injection surface is arranged between the active layer and the light extraction surface; and a plurality of anode-cathode pairs (228, 229) deposited over, and in conductive electrical communication with, the plurality of active layer portions (222-1, 222-2, 222-3); wherein each active layer portion (222-1, 222-2, 222-3) of the plurality of active layer portions (222-1, 222-2, 222-3) comprises a different anode-cathode pair (228, 229) of the plurality of anode-cathode pairs (228, 229) and is configured to illuminate a different substrate portion (342-1, 342-2, 342-3) of the plurality of substrate portions (342-1, 342-2, 342-3) and transmit light through the light extraction surface of the substrate portion (342-1, 342-2, 342-3), such that the plurality of active layer portions (222-1, 222-2, 222-3) and the plurality of substrate portions (342-1, 342-2, 342-3) form a plurality of pixels (344a, 344b, 344c); characterised in that the light extraction surface of each substrate portion (342-1, 342-2, 342-3) comprises a light extraction surface recess between pixel sidewalls of the plurality of pixels (344a, 344b, 344c), the pixel sidewalls comprising sides of each substrate portion (342-1, 342-2, 342-2); and the pixelated-LED chip further comprises a reflective layer on the pixel sidewalls including sides of each substrate portion (342-1, 342-2, 342-3).