Crystals for a semiconductor radiation detector and method for making the crystals
A method for a growing solid-state, spectrometer grade II-VI crystal using a high-pressure hydrothermal process including the following steps: positioning seed crystals in a growth zone of a reactor chamber; positioning crystal nutrient material in the nutrient zone of the chamber; filling the reactor with a solvent fluid; heating and pressuring the chamber until at least a portion of the nutrient material dissolves in the solvent and the solvent becomes supercritical in the nutrient zone; transporting supercritical from the nutrient zone to the growth zone, and growing the seed crystals as nutrients from the supercritical fluid deposit on the crystals.
1. A method for growing Cadmium Telluride (CdTe) and Cadmium Zinc Telluride (CZT) crystal comprising:
positioning a plurality of CZT or CdTe seed crystals in a growth zone of a reactor chamber divided by a porous baffle into the growth zone and a nutrient zone;
positioning CZT or CdTe nutrient material in the nutrient zone;
filling the reactor chamber with a solvent fluid;
pressurizing the reactor such that the solvent fluid becomes supercritical;
heating the reactor such that the nutrient zone is warmer than the growth zone;
dissolving the nutrient material into the supercritical fluid;
transporting the supercritical fluid with dissolved nutrient through the baffle and to the growth zone, and
growing crystals from the seed crystals as the dissolved nutrients deposit on the crystals, wherein the growth zone temperature is at least 450° C. and the reactor pressure is at least 700 bar.
2. The method of claim 1 further comprising heating the nutrient zone to a temperature that is at least 5° C. different than the growth zone, and transporting the supereritical fluid is by convection.
3. The method of claim 1 wherein the solvent fluid comprises a mineralizer.
4. The method of claim 1 wherein positioning the seed crystals further comprises suspending the seed crystals in the chamber.
5. The method of claim 1 wherein positioning the seed crystals further comprises suspending more than one hundred seed crystals in the chamber.
6. The method of claim 1 , further comprising sealing the reactor chamber and subsequently placing the sealed reactor chamber in a high pressure apparatus and thereafter performing the step of growing the crystals.
7. The method of claim 6 wherein the high pressure apparatus is a zero-stroke-type pressure apparatus.
8. The method of claim 1 , wherein the CdTe or CZT nutrient material further comprises at least one compensatory dopant.
9. The method of claim 8 , wherein the at least one compensatory dopant is selected from a group consisting of: Cl, Ge, Sn, In, B, Al, Ga, Tl, C, Si, Pb, N, P, As, Sb, Bi, F, Br, I, a transition metal, a rare earth metal, and H.