Formation behavior of Be_xZn_(1-x) O alloys grown by plasma-assisted molecular beam epitaxy

摘要

We report the phase formation behavior of Be_xZn_(1-x)O 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 Be_xZn_(1-x)O alloys with intermediate Be composition resulted from large internal strain induced by large lattice mismatch between BeO and ZnO.