RESPONSE OF ASYMMETRIC DEVICES BASED ON CARBON NANOTUBES ON SUB-TERAHERTZ RADIATION

 

A. I. Kardakova ¹, G. E. Fedorov ^1,2, I. A. Gayduchenko ^1,2, I. A. Charayev ¹, B. M. Voronov ¹, M. I. Finkel ¹, G. N. Goltsman ¹

¹ Moscow State Pedagogical University, Moscow

² National Research Centre “Kurchatov Institute”, Moscow

 

The paper is received on October 28, 2014

 

Abstract. In this paper we report on the response of the asymmetric devices based on carbon nanotubes (CNT) on the sub-terahertz radiation. Sensing element of the devices is a dense CNTs network formed by chemical vapor deposition near the catalytic island. Asymmetry of the investigated devices is inhomogeneous morphology of the CNT film which contacted with the metal electrodes. One of the electrodes contacts the part of the CNT-nets which is on the catalytic island where most of the nanotubes are suspended. The second contact connects to the other part of the CNT-network in which the nanotubes are in direct contact with the substrate. This results in the device's asymmetry associated with different thermal contact of the CNT film with the substrate. Under the radiation with a frequency of 140 GHz the DC voltage is observed at zero current bias. Analysis of the dependence of the response on the incident radiation power and the gate voltage in a wide temperature range suggests that the observed effect has a dual nature: thermal and photovoltaic. Volt-watt sensitivity of the device at room temperature exceeds the values which were earlier reported for detectors based on CNTs for submillimeter and THz ranges.

Key words: carbon nanotubes, THz detectors.