Abstract: An apparatus for producing diamond in a deposition chamber including a heat-sinking holder for holding a diamond and for making thermal contact with a side surface of the diamond adjacent to an edge of a growth surface of the diamond, a noncontact temperature measurement device positioned to measure temperature of the diamond across the growth surface of the diamond and a main process controller for receiving a temperature measurement from the noncontact temperature measurement device and controlling temperature of the growth surface such that all temperature gradients across the growth surface are less than 20° C.

Abstract: A single crystal diamond grown by microwave plasma chemical vapor deposition has a hardness of 50–90 GPa and a fracture toughness of 11–20 MPa m1/2. A method for growing a single crystal diamond includes placing a seed diamond in a holder; and growing single crystal diamond at a temperature of about 1000° C. to about 1100° C. such that the single crystal diamond has a fracture toughness of 11–20 MPa m1/2.

Abstract: A single crystal diamond grown by microwave plasma chemical vapor deposition annealed at pressures in excess of 4.0 GPa and heated to temperature in excess of 1500 degrees C. that has a hardness of greater than 120 GPa. A method for manufacture a hard single crystal diamond includes growing a single crystal diamond and annealing the single crystal diamond at pressures in excess of 4.0 GPa and a temperature in excess of 1500 degrees C. to have a hardness in excess of 120 GPa.

Abstract: An apparatus for producing diamond in a deposition chamber including a heat-sinking holder for holding a diamond and for making thermal contact with a side surface of the diamond adjacent to an edge of a growth surface of the diamond, a noncontact temperature measurement device positioned to measure temperature of the diamond across the growth surface of the diamond and a main process controller for receiving a temperature measurement from the noncontact temperature measurement device and controlling temperature of the growth surface such that all temperature gradients across the growth surface are less than 20° C.

Abstract: An apparatus for producing diamond in a deposition chamber including a heat-sinking holder for holding a diamond and for making thermal contact with a side surface of the diamond adjacent to an edge of a growth surface of the diamond, a noncontact temperature measurement device positioned to measure temperature of the diamond across the growth surface of the diamond and a main process controller for receiving a temperature measurement from the noncontact temperature measurement device and controlling temperature of the growth surface such that all temperature gradients across the growth surface are less than 20° C.

Abstract: A cubic form of C.sub.3 N.sub.4 with a zero-pressure bulk modulus exceeding that of diamond. The product is prepared by combining carbon and nitrogen at a pressure of 120,000 to 800,000 atmosphere and a temperature of 1000-3000.degree. C.