For the reactors used in the manufacture of LED’s there are more promising materials than the ones currently in use, the researchers point out.
There are many new possibilities for the development of gallium nitride (GaN) used in the production LEDs. One of the most promising production methods of gallium nitride is the ammonothermal method which uses a reactor filled up with liquid ammonia. The method is identical with the hydrothermal method utilised in the production of quartz, in which water is used instead of ammonia.
However, the high temperature inside the ammonothermal reactor combined with a pressure 2,500 times the atmospheric pressure and the corrosive effects of the so-called supercritical fluid pose a challenge to the reactor chamber and thus to the manufacture of LED materials. To find a solution to the problem, Aalto University Post-Doctoral Researcher Sami Suihkonen and a research group from the University of California, Santa Barbara led by Nobelist in Physics Shuji Nakamura and Post-Doctoral Researcher Siddha Pimputkarsystematically analysed the behaviours of 35 metals, 2 metalloids and 17 different ceramic materials with 3 different supercritical fluid chemistries heated to a temperature of 572 degrees Celsius.
In the ammonothermal method, the energy contained in the reactor corresponds roughly to a stick of dynamite.
– In the ammonothermal method, the energy contained in the reactor corresponds roughly to a stick of dynamite, making the conditions fairly hostile, Sami Suihkonen sums up.