Radio Frequency Carbon Nanotube Thin-Film Bolometer

A radio frequency bolometer was realized using a thermistor fabricated from a carbon nanotube thin-film deposited on a sapphire substrate. Power detection performance was characterized at room and liquid nitrogen temperatures. With the thermistor held at a temperature of 15 °C, the bolometer's sensitivity of 915-MHz test signals was found to be 0.36 mV/mW, and power levels as low as -45 dBm could be detected with a 20-s integration time constant. The sensitivity increased to 2.3 mV/mW when the thermistor was cooled to -193 °C. Experiments over the temperature range of 15 °C-240 °C indicate that internanotube mechanisms dominate power detection at temperatures below a value of approximately 200 °C and that intrananotube mechanisms (primarily Joule-heating) dominate at higher temperatures.