Table 4.

Summary of related SAW sensors for gas detection

Piezoelectric materials	Device frequency (MHz)	Sensing layer	Target	LOD	Frequency shift	Temp	Ref
Y-Z LiNbO${}_3$ delay lines	860	ZIF-8	${\text{CO}}_2$	0.91ppm/vol.	1.11 rad.	RT	[216]
Y-Z LiNbO${}_3$ delay lines	860	ZIF-8	CH4	16.6 ppm/vol	4.58 rad.	RT	[216]
Y-Z LiNbO${}_3$delay lines	436	ZIF-8	CH4	7.01 ppm/vol	0.136 rad.	RT	[215]
Y-Z LiNbO${}_3$delay lines	436	ZIF-8	${\text{CO}}_2$	0.38ppm/vol	1.396 rad.	RT	[215]
ST-cut quartz.	434.15	Nickel-Alanine- Graphene.	${\text{CO}}_2$	200 ppm.	2.07 Hz/ppm	RT	[336]
ST-cut quartz.	433.8	AuNR.	VOCs	2.64 ppm	n/g.	RT	[110]
ST-cut quartz.	433	Graphene.	DMMP	10 ppm	−1.4KHz/ppm.	25–100 °C	[337]
ST-cut quartz.	200	GO Nanofilm.	CH3	500 ppb	620 Hz/500 ppb.	RT	[338]
ST-cut quartz.	200	Bi${}_2$S${}_3$ nanobelts	NO2	1.2 ppm.	2 kHz/10 ppm.	RT	[339]
ST-cut quartz.	200	ZnO-Al${}_2$O${}_3$.	H2S	10 ppb.	500 Hz/10 ppb.	RT	[340]
ST-cut quartz.	200	boehmite.	NH3	10 ppm	1540 Hz/10ppm	RT	[341]
ST-cut quartz.	200	CuO-Al2O3	H2S	5 ppb	15 KHz/1ppm.	RT	[342]
ST-cut quartz.	200	Nitrogen doped Diamond.	NH3	100 ppb	0.65 KHz/100ppb.	RT	[343]
ST-cut quartz.	200	SiO${}_2$, TiO${}_2$.	NO2	16 ppm.	112 KHz/40ppm.	RT	[218]
ST-cut quartz.	200	PbS.	NO2	10 ppm.	9.8 KHz/ppm	RT	[217]
ST-cut quartz.	99.5	ZnO.	NO2	16 ppm.	112 KHz/40ppm.	RT	[344]
ST-cut quartz.	198.98	CuO.	H2S	500 ppb.	−1200Hz/500 ppb.	RT	[345]

n/g $=$ Not Given