Nanometer scale GaAs quantum well wire (QWW) arrays with lateral dimensions in the range of 10-70 nm and a period of 200 nm have been fabricated in the GaAs/AlGaAs system using X-ray nanolithography patterning and overgrowth by a low pressure metalorganic vapor phase epitaxy (LP-MOVPE) technique. The QWW structures were fabricated by post-growth patterning of a thin GaAs film on a AlGaAs-coated substrate followed by AlGaAs deposition, or by continuous in-situ deposition of a GaAs/AlGaAs QWW structure on a prepatterned GaAs substrate. Although cross-sectional transmission electron microscopy showed no structural defects in either QWW fabrication process, photoluminescence (PL) was only observed in the in-situ-deposited structures. Strong polarization dependence of the PL peak withrespect to wire orientation has been confirmed and evidence of lateral confinement was observed. © 1991.