Selective growth of diamond structures through seeding by Q-carbon fibers

This paper focuses on the selective large-area growth of continuous diamond structures using carbon fibers made from polyacrylonitrile (PAN). Here, we show that carbon fibers made from –(C3H3N)- PAN monomers can be carbonized to Q-carbon type structures. These PAN-derived amorphous carbon fibers can be directly used to seed diamond growth. When these fibers are treated with nanosecond laser pulses, Q-carbon converts directly into nanodiamonds. Q-carbon and nanodiamonds provide barrierless nucleation for diamond growth. and convert entire fiber into diamond structures. We provide detailed characterization of resulting diamond structures and discuss their growth characteristics. From these experimental results, we provide a mechanism of nucleation of metastable phase of diamond and the formation of continuous diamond films. These carbon fibers, with and without laser treatment, can be used for barrierless nucleation and seeding diamond films over a large area for wafer-scale integration. Using this technique, we demonstrate that carbon fibers can be used to grow diamond structures selectively to create diamond rings and strings and thick diamond plates for thermal management of silicon based integrated circuits and gallium nitride based high power and high current devices.