We report the hydrogen-sensing response on low-cost-solution-derived
ZnO nanorods (NRs) on a glass substrate, integrated with aluminum
as interdigitated electrodes (IDEs). The hydrothermally grown ZnO
NRs on ZnO seed-layer-glass substrates are vertically aligned and
highly textured along the
c
-axis (002 plane) with
texture coefficient ∼2.3. An optimal hydrogen-sensing response
of about 21.46% is observed for 150 ppm at 150 °C, which is higher
than the responses at 100 and 50 °C, which are ∼12.98
and ∼10.36%, respectively. This can be attributed to the large
surface area of ∼14.51 m
2
/g and pore volume of ∼0.013
cm
3
/g, associated with NRs and related defects, especially
oxygen vacancies in pristine ZnO nanorods. The selective nature is
investigated with different oxidizing and reducing gases like NO
2
, CO, H
2
S, and NH
3
, showing relatively
much lower ∼4.28, 3.42, 6.43, and 3.51% responses, respectively,
at 50 °C for 50 ppm gas concentration. The impedance measurements
also substantiate the same as the observed surface resistance is initially
more than bulk, which reduces after introducing the hydrogen gas during
sensing measurements. The humidity does not show any significant change
in the hydrogen response, which is ∼20.5 ± 1.5% for a
large humidity range (from 10 to 65%). More interestingly, the devices
are robust against sensing response, showing no significant change
after 10 months or even more.