BaCuO 2 thin films were fabricated on SrTiO 3 substrates by laser MBE to elucidate the conditions for two-dimensional heteroepitaxial growth of the infinite-layer structure. The fine streak pattern and intensity oscillations observed by in situ reflection high-energy electron diffraction (RHEED) verified that tetragonal BaCuO 2 (001) was grown in a two-dimensional unit cell-by-cell mode. Effective carrier injection into the BaCuO 2 films was investigated in two different modes, i.e. homogeneous and molecular-layer dopings. In the former mode, 1 mol% of Ba was substituted to form a (Na 0 . 0 1 , Ba 0 . 9 9 )CuO 2 film. In the latter, BaCuO 2 and (Na 0 . 0 1 , Ba 0 . 9 9 )CuO 2 molecular layers were alternately deposited to form carrier modulated multilayered films. Both homogeneous BaCuO 2 and (Na 0 . 0 1 , films were semiconductive, whereas the carrier modulated multilayered films turned out to be metallic without showing any indication of superconductivity at 4 K and above.