We　have　developed　a　vapor-liquid-phase　combined,　layer-by-layer　epitaxial　growth　strategy　for　fabricating　ultralong　ZnO　one-dimensional　vertical　arrays.　A　key　point　is　the　activation　of　the　second　top　epitaxial　growth　by　treating　shorter　arrays　in　a　growth　solution.　By　alternating　solution-　and　VS-growth　steps　for　three　times,　we　can　tune　the　length　of　the　1D　arrays　from　41　to　150　mu　m.　The　arrays　were　found　to　show　an　excellent　photoelectrocatalytic　activity　under　UV　irradiation,　higher　than　that　of　high-performance　TiO2　nanotube　arrays.　(C)　2013　Elsevier　B.V.　All　rights　reserved.