Method for growing GZO (ZnO:Ga) crystals

A method for growing GZO (ZnO:Ga) crystals, the method comprising:

• (1) providing powders including ZnO and Ga2O3 based on stoichiometry of ZnO:
• x wt % Ga2O3, wherein x=0˜1.0, and the powders including ZnO and Ga2O3 being ball-milled, oven-dried, and then sieved by 200 mesh;
• (2) loading the powers including ZnO and Ga2O3 into a rubber balloon to be vacuumed, sealed, and isostatic pressed under pressure of 70 MPa to form rods that are compact and uniform;
• (3) sintering the rods at 1250˜1300° C. for 24˜48 hours using a vertical furnace to form first polycrystalline rods;
• (4) providing powders including B2O3, MoO3, Nb2O5, and ZnO based on a mole ratio of 9.3:16.3:6.7:67.7, wherein the powders including B2O3, MoO3, Nb2O5, and ZnO being ball-milled and oven-dried and sieved by 200 mesh;
• (5) loading the powers including B2O3, MoO3, Nb2O5, and ZnO in a rubber balloon to be vacuumed, sealed, and isostatic pressed under pressure of 70 M Pa to form compact and uniform flux rods;
• (6) sintering the compact and uniform flux rods at 1100° C. for 24 hours by a vertical furnace to form second polycrystalline rods;
• (7) cutting the second polycrystalline rods into flux cross-section wafers with 3˜5 mm in thickness;
• (8) cutting a part of feed rod from the first polycrystalline rods fixed as a seed crystal to a bracket that located on a lower rotary shaft;
• placing a flux cross-section wafer of the flux cross-section wafers on the cross-section wafers;
• adjusting the flux cross-section wafer to be horizontal and middle, adjusting a feed rod or a upper rod to be middle;
• loading a quartz tube was such that a tip of feed rod is close to the flux cross-section wafer and removed to a center of a focus area of halogen lamps together;
• increasing a out power of halogen lamps to 1028 W at a rate of 60 W/min;
• making a upper surface of the flux cross-section wafer melt mildly;
• letting the upper rod falling down slowly and adhering to the flux cross-section wafer;
• pulling up together with the flux cross-section wafer;
• increasing the out power to 1100 W at a slower rate of 20 W/min to make the feed rod's tip melt completely together with the flux cross-section wafer for 0.5 hour;
• connecting the upper and lower rods connected each other by molten flux and counter-rotated for 1 hour at the upper and lower rates of 25˜35 rpm and 25˜35 rpm respectively;
• setting a growth rate to 0.3˜0.5 mm/h and starting crystal growth after molten zone became stable;
• adjusting the out power of halogen lamp to be 1100˜1360 W slowly depending on the Gallium oxide component;
• (9) setting a cooling time of the grown crystals to a room temperature for 4.5˜10 hours when growth process is finished.