An apparatus for controlling a thickness of a crystalline ribbon grown on a surface of a melt includes a crucible configured to hold a melt; a cold initializer facing an exposed surface of the melt; a segmented cooled thinning controller disposed above the crucible on a side of the crucible with the cold initializer; and a uniform melt-back heater disposed below of the crucible opposite the cooled thinning controller. Heat is applied to the ribbon through the melt using a uniform melt-back heater disposed below the melt. Cooling is applied to the ribbon using a segmented cooled thinning controller facing the crystalline ribbon above the melt.

A class of erbium-doped silicate crystals have a general chemical formula of (Er.sub.xYb.sub.yCe.sub.zA.sub.(1-x-y-z)).sub.3RM.sub.3Si.sub.2O.sub.14, in which the range of x is 0.002 to 0.02, y is 0.005 to 0.1, and z is 0 to 0.15; A is one, two or three elements selected from Ca, Sr, or Ba; R is one or two elements selected from Nb or Ta; M is one or two elements selected from Al or Ga. Using one of such crystals as a gain medium and a diode laser at 940 nm or 980 nm as a pumping source, a 1.5 μm continuous-wave solid-state laser with high output power and high efficiency, as well as a pulse solid-state laser with high energy and narrow width can be obtained.

A method of forming an organic solid crystal (OSC) thin film includes forming a layer of a non-volatile medium material over a surface of a mold, forming a layer of a molecular feedstock over a surface of the non-volatile medium material, the molecular feedstock including an organic solid crystal precursor, forming crystal nuclei from the organic solid crystal precursor, and growing the crystal nuclei to form the organic solid crystal thin film. An organic solid crystal (OSC) thin film may include a biaxially-oriented organic solid crystal layer having mutually orthogonal refractive indices, n.sub.1≠n.sub.2≠n.sub.3.

A method for growing a crystal boule includes the steps of: periodically pulling upwardly a seed crystal dipped into a melt in a crucible to grow a first neck of the crystal boule below the seed crystal; and continuously pulling upwardly the seed crystal and the first neck of the crystal boule to grow a second neck of the crystal boule below the first neck.

A method for growing a crystal boule includes the steps of: periodically pulling upwardly a seed crystal dipped into a melt in a crucible to grow a first neck of the crystal boule below the seed crystal; and continuously pulling upwardly the seed crystal and the first neck of the crystal boule to grow a second neck of the crystal boule below the first neck.

Crystal pulling systems having composite polycrystalline silicon feed tubes, methods for forming such tubes, and methods for forming a single crystal silicon ingot with use of such tubes. The composite polycrystalline silicon feed tubes include quartz and at least one dopant. The composite polycrystalline silicon feed tube may be made by a slip cast method.

A substrate for a surface acoustic wave device is constituted of a piezoelectric material and includes a first surface on which a surface acoustic wave propagates, and a second surface located opposite to the first surface. The second surface has an arithmetic mean roughness (Ra) of 0.2 μm to 0.4 μm, and there is satisfied either of the relationship between the arithmetic mean roughness (Ra) and mean spacing (S) of local peaks of Ra/S≥11, and the relationship between the arithmetic mean roughness (Ra) and mean spacing (Sm) of irregularities of Ra/Sm≥6.7. Further, the second surface has a maximum height (Rmax) of 2.5 μm to 4.5 μm, and there is satisfied either of the relationship between the maximum height (Rmax) and mean spacing (S) of local peaks of Rmax/S≥130, and the relationship between the maximum height (Rmax) and mean spacing (Sm) of irregularities of Rmax/Sm≥80.

A growth device and method for low-stress crystals are provided, which relate to the field of preparation of crystals, in particular to a device and method for preparing low-stress and low-defect crystals by using a pulling method. The growth device includes a furnace body; a crucible and a heating and insulation system which are arranged at a bottom of the furnace body; a crystal pulling mechanism, and a quartz observation window; the device further includes a liftable heating mantle mechanism including a heating mantle body, a heating mantle supporting component, a heating wire arranged around the heating mantle body, and a heating mantle lifting mechanism. The method includes: after crystals are pulled out of a melt, covering the crystals with a liftable heating mantle mechanism. By the use of the present invention, a temperature gradient inside the crystals in a crystal growth process and in a cooling process after the crystals are pulled can be reduced, thereby reducing the crystal stress, reducing defects, and avoiding the crystals from being cracked; and at the same time, the temperature gradient in the melt is maintained, thereby guaranteeing a stable crystal growth process and ensuring the yield of the crystals.

A growth device and method for low-stress crystals are provided, which relate to the field of preparation of crystals, in particular to a device and method for preparing low-stress and low-defect crystals by using a pulling method. The growth device includes a furnace body; a crucible and a heating and insulation system which are arranged at a bottom of the furnace body; a crystal pulling mechanism, and a quartz observation window; the device further includes a liftable heating mantle mechanism including a heating mantle body, a heating mantle supporting component, a heating wire arranged around the heating mantle body, and a heating mantle lifting mechanism. The method includes: after crystals are pulled out of a melt, covering the crystals with a liftable heating mantle mechanism. By the use of the present invention, a temperature gradient inside the crystals in a crystal growth process and in a cooling process after the crystals are pulled can be reduced, thereby reducing the crystal stress, reducing defects, and avoiding the crystals from being cracked; and at the same time, the temperature gradient in the melt is maintained, thereby guaranteeing a stable crystal growth process and ensuring the yield of the crystals.

The present disclosure provides a method for regulating an inert gas flow in a crystal pulling furnace, a method for preparing monocrystalline silicon, and monocrystalline silicon. The method for regulating an inert gas flow includes introducing the inert gas into a main furnace chamber of the crystal pulling furnace from an auxiliary furnace chamber of the crystal pulling furnace, and regulating a flow direction of the inert gas flow introduced into the auxiliary furnace chamber of the crystal pulling furnace.