Formation behavior of BexZn1-xO alloys grown by plasma-assisted molecular beam epitaxy

We report the phase formation behavior of BexZn1-xO alloys grown by plasma-assisted molecular beam epitaxy. We find the alloy with low-and high-Be contents could be obtained by alloying BeO into ZnO films. X-ray diffraction measurements shows the c lattice constant value shrinks, and room temperature absorption shows the energy band-gap widens after Be incorporated. However, the alloy with intermediate Be composition are unstable and segregated into low-and high-Be contents BeZnO alloys. We demonstrate the phase segregation of BexZn1-xO alloys with intermediate Be composition resulted from large internal strain induced by large lattice mismatch between BeO and ZnO. (C) 2013 AIP Publishing LLC.