The ohmic contact and photoresponse of a ZnO single crystal film by metalorganic chemical vapor deposition (MOCVD) were investigated. The electrical and photoresponsive changes in the ZnO film due to RF sputter deposition of SiO2 (antireflection coating) were also discussed. The experimental results show that the non-alloyed Al/Au metallization scheme forms good ohmic contact on n-type ZnO, RF sputter deposition of SiO2 induces defects which behave as carrier traps and prolong response time, and the photoresponse of ZnO epitaxial film deteriorates with time.