NOVELTY - The method involves providing a polycrystalline substrate (110) comprising metal and randomly oriented grains (156, 158). A buffer layer (120) comprising a set of spaced-apart islands is formed over the substrate. A semiconductor layer (150) is formed over the buffer layer. A mask is formed over the semiconductor layer. Motion is induced between the substrate and a high-temperature region along travel direction, where the grains of the semiconductor layer grow from the mask preferentially along the travel direction to form a single-crystalline portion of the semiconductor layer.    USE - Method for forming a polycrystalline semiconductor structure for a current solar cell i.e. multijunction photovoltaic cell. Can also be used for a flat-panel display, LED and a laser.    ADVANTAGE - The method enables selecting and enlarging grain size of a polycrystalline semiconductor film so as to minimize deleterious impact of processing the films. The method enables reactive material to reduce melting point of the semiconductor layer, thus enhancing wetting of the semiconductor layer to a buffer layer to improve uniformity of the semiconductor layer. The method enables utilizing lower temperature processing enabled via use of residual stress in the semiconductor film during recrystallization, thus minimizing process challenges such as agglomeration and thermal expansion mismatch. The method enables crystallization temperature for germanium to be 300 degree celsius depending on deposition conditions, so that deleterious volume changes in the semiconductor layer are avoided during recrystallization processes. The method enables utilizing a polycrystalline template formed on a flexible metal substrate at low cost with quality similar to that a polycrystalline semiconductor substrate.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of layer structures.    Layer structure (100)    Polycrystalline substrate (110)    Buffer layer (120)    Semiconductor layer (150)    Randomly oriented grains (156, 158)