Fabrication　of　reliable　large-sized　p-ZnO　is　a　major　challenge　to　realise　ZnO-based　electronic　device　applications.　Here　we　report　a　novel　technique　to　grow　high-quality　free-standing　undoped　acceptor-rich　ZnO　(A-ZnO)　microtubes　with　dimensions　of　similar　to　100　mu　m　(in　diameter)　x　5　mm　(in　length)　by　optical　vapour　supersaturated　precipitation.　The　A-ZnO　exhibits　long　lifetimes　(＞1　year)　against　compensation/lattice-relaxation　and　the　stable　shallow　acceptors　with　binding　energy　of　similar　to　127　meV　are　confirmed　from　Zn　vacancies.　The　A-ZnO　provides　a　possibility　for　a　mimetic　p-n　homojunction　diode　with　n(+)-ZnO:Sn.　The　high　concentrations　of　holes　in　A-ZnO　and　electrons　in　n(+)-ZnO　make　the　dual　diffusion　possible　to　form　a　depletion　layer.　The　diode　threshold　voltage,　turn-on　voltage,　reverse　saturated　current　and　reverse　breakdown　voltage　are　0.72　V,　1.90　V,　＜10　mu　A　and　＞15　V,　respectively.　The　A-ZnO　also　demonstrates　quenching-free　donor-acceptor-pairs　(DAP)　emission　located　in　390-414　nm　with　temperature　of　270-470　K.　Combining　the　temperature-dependent　DAP　violet　emission　with　native　green　emission,　the　visible　luminescence　of　A-ZnO　microtube　can　be　modulated　in　a　wide　region　of　colour　space　across　white　light.　The　present　work　opens　up　new　opportunities　to　achieve　ZnO　with　rich　and　stable　acceptors　instead　of　p-ZnO　for　a　variety　of　potential　applications.