An optoelectronic device (40; 90; 95; 100; 105) comprising: a support; blocks of a semiconductor material, resting on the support and each comprising a first surface on the side opposite to the support and lateral walls; a nucleation layer on each first surface; a first electrically-insulating layer (60, 62) covering each nucleation layer and comprising an opening exposing a portion of the nucleation layer, for each block, the assembly comprising the block, the nucleation layer, and the first electrically-insulating layer (60, 62) being included in a pedestal; a semiconductor element (72, 92) resting on each first insulating layer and in contact with the nucleation layer covered with said first insulating layer in the opening; a shell covering each semiconductor element and comprising an active layer capable of emitting or of absorbing an electromagnetic radiation; a second electrically-insulating layer covering at least a lower portion of each semiconductor element (72, 92) and extending over the lateral walls of each pedestal and over a lower portion of the shell; a first electrically-conductive layer, at least partly transparent to said radiation and covering each shell and the portion of the second electrically-insulating layer extending over the shell, the second electrically-insulating layer being located between the shell and the first electrically-conductive layer; and a second electrically-conductive layer, reflecting said radiation, extending between the semiconductor elements, extending over at least a portion of the lateral walls of the blocks, and extending over the first electrically-insulating layer, the first electrically-insulating layer being located between the second electrically-conductive layer and the second electrically-insulating layer, which second conductive layer does not cover the shells. a support; blocks of a semiconductor material, resting on the support and each comprising a first surface on the side opposite to the support and lateral walls; a nucleation layer on each first surface; a first electrically-insulating layer (60, 62) covering each nucleation layer and comprising an opening exposing a portion of the nucleation layer, for each block, the assembly comprising the block, the nucleation layer, and the first electrically-insulating layer (60, 62) being included in a pedestal; a semiconductor element (72, 92) resting on each first insulating layer and in contact with the nucleation layer covered with said first insulating layer in the opening; a shell covering each semiconductor element and comprising an active layer capable of emitting or of absorbing an electromagnetic radiation; a second electrically-insulating layer covering at least a lower portion of each semiconductor element (72, 92) and extending over the lateral walls of each pedestal and over a lower portion of the shell; a first electrically-conductive layer, at least partly transparent to said radiation and covering each shell and the portion of the second electrically-insulating layer extending over the shell, the second electrically-insulating layer being located between the shell and the first electrically-conductive layer; and a second electrically-conductive layer, reflecting said radiation, extending between the semiconductor elements, extending over at least a portion of the lateral walls of the blocks, and extending over the first electrically-insulating layer, the first electrically-insulating layer being located between the second electrically-conductive layer and the second electrically-insulating layer, which second conductive layer does not cover the shells.