Single-crystalline ZnO nanowires (NWs) were directly grown on Zn/glass substrates by using a low-temperature (i.e., 40 • C) supercritical carbon dioxide (SCCO 2 ) fluid method. The optical, physical, and field-emission (FE) characteristics of the SCCO 2 -synthesized ZnO nanostructures are systematically investigated. ZnO NWs exhibited the low turn-on field of 3.16 V/μm at a current density of 10 μA/cm 2 and a low threshold field of 4.38 V/μm at a current density of 1 mA/cm 2 . The current fluctuation of ZnO emitters was less than 8% at 5.3 V/μm in 12 h. The excellent FE properties of SCCO 2 -synthesized ZnO emitters at low temperature make them a superior candidate for FE-based display devices.Index Terms-Field emission (FE), low temperature, nanowire (NW), supercritical carbon dioxide (SCCO 2 ) fluid method, zinc oxide (ZnO).