The Properties and Sensing Mechanism of PdNPs-decorated Silicon Nanobelt Devices for H2 Sensing at Room Temperature

This study reports the properties and 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.PEALD of PdNPs provides high conformity and fine control of the particle size. The PdNPs-decorated SNB devices working at room temperature are characterizedat H2 concentration ranging from 10 to 1000 ppm. Instead of using the traditional steady-state response, the slope of response and the corresponding sensing mechanism are 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 μW.

本研究报告了Pd纳米颗粒（PdNPs）装饰的n+/n-/n+双结硅纳米带（SNB）器件的特性和氢气（H2）传感器传感机制。SNB器件通过CMOS工艺制备。采用等离子体增强原子层沉积（PEALD）技术将PdNPs作为传感材料沉积在SNB器件的Al2O3介电层上。PEALD技术为PdNPs的沉积提供了高一致性及对粒子尺寸的精细控制。在室温下工作的PdNPs装饰的SNB器件在10至1000 ppm的H2浓度范围内进行了表征。不同于传统的稳态响应，本研究呈现了响应斜率和相应的传感机制，以估算浓度并缩短响应时间。在10至1000 ppm的H2检测中，实现了超过60%的响应时间提升。为了缩短恢复时间，通过偏置电压为11 V、持续时间为240 s的设备局部焦耳加热（DLJH）方法，将器件恢复至基线。在偏置电压为1 V的条件下，室温下的H2传感仅需消耗68.39 μW的功率。