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Transition metal nitrides (TMN) are promising material alternative to replace noble metals in the field of plasmonic applications, especially surface‐enhanced Raman spectroscopy (SERS). Here we demonstrate a practical surface enhanced Raman spectroscopy (SERS) substrate using zirconium nitride (ZrN) thin films grown by reactive gas‐timing (RGT) rf magnetron sputtering. The tailored properties of ZrN thin film exploited for SERS activity could be achieved to obtain a highly sensitive ZrN thin film SERS substrate with the enhancement factor (EF) of 1.24 × 106 and 4.8 %RSD at 1626 cm‐1 toward methylene blue (MB) analyte which are comparable to the optimized Au sputtered thin films (EF=1.18 × 106 and with 5.1%RSD). We find that the spatial plasmonic hotspots on the surface of ZrN SERS substrate controlled by the turn‐on timing of Ar:N2 sputtered gas sequence, leading to the discrete conductive surface profile, strongly relates to non‐stoichiometric composition and the degree of (200)‐oriented texture at the surface of ZrN thin film. Furthermore, ZrN thin film SERS substrates exhibit an excellent recyclability more than 30 cycles with simple cleaning process and a storage time longer than 6 months. The detection and reusability of ZrN SERS substrate on the low concentration of trinitrotoluene (TNT) for homeland security are also performed. [ABSTRACT FROM AUTHOR]

The development of an immunosensor‐based biosensor to detect the human serum albumin (HSA) was developed as a low‐cost and label‐free electrical detection through silicon nitride ion‐sensitive field‐effect transistor (Si3N4‐ISFET). This sensor was functionalized using 3‐Aminopropyltriethoxysilane (APTES). The silanized Si3N4‐ISFET surface was covalently linked with antibody against HSA (Anti‐HSA) via glutaraldehyde (GA) to function as an HSA immunosensor for detection of HSA. The interaction between HSA and Anti‐HSA on this device is monitored by changing of the gate potential at a constant drain current of 50 μA. The relationship between HSA concentration and the gate potential change of HSA immunosensor is linear up to 500 μg/ml with a detection limit of 5 μg/ml. This HSA immunosensor offers a good precision in both intra‐ and inter‐assay with a relative standard deviation of 6.61%, 7.48%, 10.69%, and 9.67%, 13.16%, 15.52% for 100, 200, and 400 μg/ml. The average percentage of recovery assay for the concentration of 32.1, 102.1, and 202.1 μg/ml is 96.55%. This sensor also provides its satisfactory selectivity when testing with Bence Jones protein solution. In addition, the results that was done by this HSA immunosensor is similar to the conventional method using immunoturbidimetric detection with a linear regression of 0.99; n = 40 with a paired sample t‐test of <0.01. Thus, this HSA immunosensor could be applied to urinary microalbumin detection because of its simplicity and satisfactory correlation value. [ABSTRACT FROM AUTHOR]