Review—Nanopillar Structure in the Direction of Optical Biosensor On-Chip Integration

Abstract

Biosensors based on nanomaterial have attracted so much interest due to their high-performance potential. Its structure allows the biosensor to have high sensitivity and selectivity. Nanopillar (NPLA) is one class of material with unique properties, especially optical properties. Its unique properties cause it to be the structure that has drawn so much attention recently. The advantages owned by NPLA, including high surface area and its unique optical properties, provide the possibility to build a sensitive layer for a biosensor that is very promising for health and medical applications. This structure also offers low-cost fabrication and can be produced on a mass scale due to its compactness and reliability. Furthermore, NPLA has a high capability to be used as optical biosensors. This article reviews diverse fabrication routes of NPLA structures. Their applications in biomolecular detection, mainly by optical approach, are highlighted. The comparison of the limit of detection of the different kinds of optical biosensors is also presented. The focus of this article lies on the possibilities of NPLA structure integrating into biosensors on-chip.

Demystifying data evaluation in the measurement of periodic structures

“…In the 1D case we commonly saw mean relative errors below 10 −6 with 50 000 samples, whereas here we do not reach such accuracy even with 2000 × 2000 = 2000 000 image pixels (for comparable noise levels). This is a direct consequence of the smaller number of periods in images and slower scaling with P. The error (7) is also larger because it is the total relative error of four vector components, instead of a single parameter T.…”

“…The former include crystal lattices and surface reconstructions at the atomic scale, periodic domains formed during crystal growth [1] or structures formed during phase transitions [2], stress-induced periodic wrinkle and ripple structures [3], self-assembled monolayers and colloidal films [4,5]. Lithographically prepared gratings, nanohole and nanopillar arrays are archetypal examples of the latter category [5][6][7][8], but it also includes patterns produced using laser interference techniques [9][10][11] or nanomachining [12]. All these structures are frequently characterised using scanning probe microscopy (SPM) and profilometry with the period/pitch or lattice vectors among the key parameters evaluated.…”