Table 2.

The oxide layers attain the best results (R_min, FWHM, sensitivity, and FOM) at the optimized thickness of Cu layer.

Thickness of Oxide Layers (nm)	Thickness of TiO2 (nm)	Thickness of Cu (nm)	Rmin at ns		FWHM (deg) at ns		δθSPR (deg) at δns = 0.005	Sn (°/RIU)	FOM (RIU−1)
			1.33	1.335	1.33	1.335
BaTiO3 (5 nm)	0	55	0.014	0.013	0.72	0.75	0.66	132	183
BaTiO3 (10 nm)	0	55	0.0097	0.0081	1.23	1.29	0.89	178	144.7
BaTiO3 (15 nm)	0	45	0.096	0.0095	4.27	4.65	2.43	486	113.8
BaTiO3 (5 nm)	5	55	0.0067	0.0061	0.69	0.71	0.66	132	191.30
BaTiO3 (10 nm)	5	55	0.0013	0.00053	1.15	1.21	0.90	180	156.5
BaTiO3 (15 nm)	5	45	0.026	0.031	4.03	4.49	2.76	552	136.97
Fe2O3 (5 nm)	5	55	0.0062	0.0072	0.96	1.003	0.71	142	147.9
Fe2O3 (10 nm)	5	50	0.017	0.034	3.28	3.6	1.41	282	85.97
Fe2O3 (11 nm)	5	45	0.0043	0.049	5.2	5.78	2.03	406	78.07
MoO3 (5 nm)	5	55	0.0046	0.0042	0.58	0.6	0.59	118	203.4
MoO3 (10 nm)	5	55	0.0014	0.001	0.75	0.77	0.65	130	173.3
MoO3 (27 nm)	5	45	0.013	0.0022	3.68	4.18	1.93	386	104.89