Characterization of carbon nanotube film-silicon Schottky barrier photodetectors

Abstract

The authors fabricate vertical geometry single-walled carbon nanotube (CNT) film/p-type silicon Schottky barrier photodetectors, where the CNT film acts as the transparent metal and silicon as the active semiconductor. The authors experimentally characterize the current-voltage, spectral responsivity, and noise properties of these devices under reverse bias. The authors find that the CNT film–Si Schottky barrier photodetectors exhibit a large photocurrent-to-dark current ratio with responsivity as high as 0.10 A/W due to the high transmittance of the CNT film. The measured current noise spectral density shows a 1/f limited behavior and scales as the square of the reverse bias current. The noise equivalent power of the devices is found to be 1.4 × 10−10 W. A comparison between CNT film devices and devices based on conventional metal electrodes is also carried out. These results provide important insights into the properties and performance of CNT film–Si Schottky barrier photodetectors.