Halide Vapor Phase Epitaxy of Mg_xZn_1-xO Layers on Zn-Polar ZnO Substrates

Abstract

High quality Mg x Zn 1Àx O layers (0 x 0:16) on Zn-polar ZnO substrates were successfully grown by halide vapor phase epitaxy (HVPE) at a high temperature of 1000 C. The Mg x Zn 1Àx O layers exhibited atomically flat surfaces, and were free from impurities. The near-bandedge emission of photoluminescence (PL) at room temperature could be varied from 3.26 to 3.56 eV with increase of the Mg concentration. PL measurements at 12 K revealed that a Mg 0:16 Zn 0:84 O layer grown by HVPE exhibited excellent optical properties.

Solid Composition Control of MgxZn1-xO in Halide Vapor Phase Epitaxy

“…Precise control of the solid composition of Mg x enhances the opportunity to apply Mg x Zn 1Àx O in various applications, including light-emitting or receiving devices for the UV spectral region, 3,4) and for two-dimensional structures. 5) Recent reports suggest that changes in the lattice constant of Mg x Zn 1Àx O from that of ZnO could be small, [6][7][8] a property that will render Mg x Zn 1Àx O/ZnO structures suitable for virtually strain-free bandgap engineering. 9) When growing compound semiconductor alloys by VPE, the unambiguous relationship between the supplied gaseous composition and the solid composition is of importance.…”

“…Recently, we have reported epitaxial ZnO and Mg x -Zn 1Àx O growth in a HVPE system using ZnCl 2 and H 2 O as source gases, 8,10) and have demonstrated that ZnO and Mg x Zn 1Àx O can be grown at the high temperature of 1000 C without any significant degradation of the growth rate. A thermodynamic approach to the ZnCl 2 -H 2 O system can well explain the dependence of growth rate on the growth conditions.…”