Abstract: Apparatus and methods for controlling gas flows in a HVPE reactor. Gas flows may be controlled by a gas focusing element. Gas injection and gas collection tubes are positioned within an outer tube and are separated from each other to define a space there between. A gas, such as HCl gas, flows over the outer surfaces of the injection and collection tubes to contain gases within the space as they flow from the injection tube to the collection tube and over a seed upon which group III nitride materials are grown. Gas flows may also be controlled by a multi-tube structure that separates gases until they reach a grown zone. A multi-tube structure may include four tubes, which separate flows of a halide reactive gas, a reaction product that flows with a carrier gas, and ammonia.

Abstract: The geometry of transition from cylindrical to rectangular shape through the conical part in hydride vapor phase epitaxial (HVPE) systems for deposition of III-nitride films is disclosed. It is used to ensure the laminar gas flow inside the growth zone of the system. For the velocity of flow within the atmospheric pressure reactor to be sufficient, the precursors are injected through the narrow diameter tubing injectors. The quartz reactor geometry is introduced to control the transition from jet to laminar flow.

Abstract: HVPE reactors and methods for growth of p-type group III nitride materials including p-GaN. A reaction product such as gallium chloride is delivered to a growth zone inside of a HVPE reactor by a carrier gas such as Argon. The gallium chloride reacts with a reactive gas such as ammonia in the growth zone in the presence of a magnesium-containing gas to grow p-type group III nitride materials. The source of magnesium is an external, non-metallic compound source such as Cp2Mg.

Abstract: A system including a gas turbine engine having a compressor portion, a combustion portion and an exhaust portion is disclosed. The system includes a first regulating nozzle for injecting water into the compressor portion, a second regulating nozzle for injecting water into the combustion portion, a third regulating nozzle for injecting water into the exhaust portion, and a condenser apparatus for extracting water from flue gases in the exhaust portion. The system further includes a pump for pumping water from the condenser apparatus to the first, second and third regulating nozzles, wherein said nozzles inject water supplied solely from the condenser apparatus, and a processor communicatively coupled to said regulating nozzles, wherein the processor is configured for transmitting control signals to the first, second and third regulating nozzles, and wherein the control signals are configured to command said regulating nozzles to inject predefined amounts of water.