Resonant tunnelling and fast switching in amorphous-carbon quantum-well structures

The need for fast electronic devices working under extreme conditions, particularly at high temperature and high voltage, led researchers to investigate the use of films based on diamond1,2,3, graphitic carbon4, amorphous carbon 5 and other carbon nanostructures6. In parallel, a different class of materials including disordered organic7,8 and inorganic9,10,11 materials has been studied, particularly for fast switching and large-area inexpensive electronics based on quantum transport9,12. However, fast-switching devices of amorphous semiconductors based on negative differential resistance or resonant tunnelling has not been achieved so far13,14. Here, we show negative differential resistance peaks, quantized conductance and bias-induced switching with a high-frequency response from amorphous-carbon quantum-well structures. We also demonstrate sufficiently large values for the phase-coherence length and delocalized conduction in these band-modulated low-dimensional disordered carbon structures, which could lead to a new generation of unusual fast-switching devices.