Direct growth of nanographene at low temperature from carbon black for highly sensitive temperature detectors

Graphene has attracted tremendous research interest owing to its widespread potential applications. However, these applications are partially hampered by the lack of a general method to produce high-quality graphene at low cost. Here, to the best of our knowledge, we use low-cost solid carbon allotropes as the precursor in plasma-enhanced chemical vapor deposition (PECVD) for the first time, and find that the hydrogen plasma and reaction temperature play a crucial role in the process. Hydrogen plasma etches carbon black, and produces graphene crystals in a high-temperature zone. Based on this finding, a modified PECVD technology is developed, which produces transparent conductive nanographene films directly on various substrates at a temperature as low as 600 °C. For application, the closely packed structure of the nanographene film enables a remarkable temperature-dependent behavior of the resistance with a ratio higher than that previously reported, indicating its great potential for usage in highly sensitive temperature detectors.