The Sensing Mechanism of PdNPs-Decorated Silicon Nanobelt Devices for H₂Sensing at Room Temperature

This study reports the sensing mechanism of Pd nanoparticles (PdNPs) decorated n+/n-/n+ double-junction silicon nanobelt (SNB) device as hydrogen (H2) gas sensor. The SNB devices are prepared via CMOS process. Plasma-enhanced atomic layer deposition (PEALD) is adopted for PdNPs deposition as sensing material on the Al2O3 dielectric of SNB devices. The PdNPs-decorated SNB devices working at room temperature are characterized at H2 concentration ranging from 10 to 1000 ppm. Instead of using the traditional steady-state response, the slope of response is presented to estimate concentration and shorten the response time. More than 60% improvement in response time has been achieved for 10 to 1000 ppm H2 detection. To reduce recovery time, device localized Joule heating (DLJH) with a bias of 11 V for 240 s is demonstrated to restore the device back to the baseline. At a bias of 1 V, H2 sensing at room temperature consumes only 68.39 ~μ W.