Electrical noise in gold nanocluster sensors

Motivated by applications to chemiresistive vapor sensing, the electrical noise properties of large-area gold nanocluster films are investigated experimentally. Measurements show thermal noise to dominate at low voltages and high frequencies, with a 1∕f noise component becoming more important at a higher voltage and a lower frequency. The latter contribution obeys the Hooge formula in its frequency, voltage, and size dependences, and with a Hooge parameter whose relatively large size is attributed to constraints imposed by Coulomb blockade and disorder. Based on these results, a detection limit for nanocluster-based chemiresistors can be projected to approach one part per billion by volume.