Growth of Bulky Single Crystalline Films of (Zn,Mg)O Alloy Semiconductors by Liquid Phase Epitaxy

Very thick (about 0.5 mm) single crystalline films of (Zn1−xMgx)O solid solution have been grown by a liquid phase epitaxy (LPE) technique. The source materials, ZnO and MgO, were dissolved in a molten PbO-Bi2O3 flux and deposited on ZnO substrates as epitaxial (Zn1−xMgx)O layers. The (Zn1−xMgx)O layers thus obtained showed high crystallinity, similar to that of the ZnO substrate, and exhibited n-type conductivity with relatively high Hall mobilities (>90 cm2 V−1 s−1 for x = 0.1 at room temperature). Moreover, the activation energy of the mobile electrons was about 50 meV, and this value was independent of the MgO fraction. Since LPE is an appropriate technique for growing large area films, we examined the growth of (Zn,Mg)O thick films on 2 in. diameter ZnO substrates. The Mg concentration in the LPE grown layer was quite uniform, and the Li concentration was two or three orders lower than an ordinary ZnO substrate.