Conventional　Ga2O3-based　solar-blind　photodetectors　typically　require　a　high　bias　voltage　for　efficient　operation,　leading　to　significant　energy　consumption.　To　address　this,　we　propose　an　alternative　approach　using　MOCVD-grown　homoepitaxial　β-Ga2O3　thin　films　on　(100)　Sn-doped　β-Ga2O3　wafer　to　develop　photodetectors　with　ultra-low　bias　and　high　gain.　A　graphene/　Ga2O3　heterojunction　device　was　fabricated,　exhibiting　an　exceptionally　low　dark　current　of　0.1nA　and　a　photocurrent　ratio　of　104　at　−5　V,　along　with　a　suppression　ratio　(R254nm/R405nm)　of　1800　at　0　V.　By　leveraging　graphene＇s　carrier-carrier　scattering　and　Ga2O3′s　UV　absorption,　the　device　achieved　a　responsivity　increase　from　0.04　mA/W　(0　V)　to　30　mA/W　(−0.5　V),　equivalent　to　a　73944　%　enhancement,　while　the　detectivity　improved　by　1096　%,　reaching　2.68　×　1012　Jones.　This　work　provides　insights　into　the　development　of　highly　sensitive,　low-power　solar-blind　UV　photodetectors.　©　2025　Elsevier　Ltd