ZnO Nanowire Field Effect Transistor for Biosensing: A Review

Abstract

The last 19 years have seen intense research made on zinc oxide (ZnO) material mainly due to the ability of converting the natural n-type material into p-type. For a long time, the p-type state was impossible to attain and maintain. The review focuses on ways of improving the doped ZnO material which acts as a channel for nanowire field effect transistor (NWFET) and biosensor. The biosensor has specific binding which is called functionalisation achieved by attaching a variety of compounds on the designated sensing area. Reference electrodes and buffers are used as controllers. Top-down fabrication processes are preferred over bottom-up because they pave way for mass production. Different growth techniques are reviewed and discussed. Strengths and weaknesses of the FET and sensor are also reviewed.

Photoluminescence of ZnO Nanowires: A Review

“…A more detailed exposition of these different growth techniques can be found in the work of Rong et al [ 35 ]. However, among these techniques, the vapor-liquid-solid technique (VLS) and hydrothermal technique are the most commonly used bottom-up ZnO nanowires growth processes [ 49 ]. These two techniques are discussed below.…”

“…As many reports attribute the origin of these emissions to the presence of defects in the ZnO structure, a brief review of the most common defects in the ZnO lattice must be introduced. Defects in the ZnO structure can be divided into extrinsic and intrinsic levels [ 49 ]. The intrinsic, sometimes called native levels, are oxygen vacancy ( V O ), zinc vacancy ( V Zn ), oxygen interstitial ( O i ), zinc interstitial (Zn i ), oxygen anti-site ( O Zn ), and zinc anti-site (Zn O ) ( Figure 6 a) [ 125 ].…”

“…As mentioned before, the literature on ZnO 1D nanostructures is vast; therefore, there are many reviews describing the different synthesis methods [ 34 , 35 ], optical [ 36 ] and electrical [ 37 ] properties, and practical applications of ZnO nanowires [ 38 , 39 ] and nanorods [ 40 ], including photocatalyst material [ 41 ], sensing platforms (chemical [ 42 ] and biological [ 43 , 44 ]), antibacterial element [ 45 ], light emissions sources(LEDs [ 46 ] and lasers [ 47 ]), dye-sensitized or thin film solar cells [ 48 ], field effect transistors [ 49 ], and piezoelectric nanogenerators [ 50 ].…”

Economic Friendly ZnO-Based UV Sensors Using Hydrothermal Growth: A Review

“…In the last few decades, semiconducting metal oxide nanoscale materials were the most likely candidates for electronic, optical, biomedical and thermal applications. They were widely used in UV lasers, sensors, field-effect transistors, field emission devices, energy harvesters, light-emitting sources, phonic devices and nanogenerators [ 3 , 4 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ]. These metal oxide materials include zinc oxide (ZnO), nickel oxide (NiO), titanium oxide (TiO 2 ), copper oxide (CuO), tin oxide (SnO 2 ), iron oxide (Fe 2 O 3 ), indium oxide (In 2 O 3 ), tungsten trioxide (WO 3 ) and vanadium oxide (V 2 O 3 ) [ 1 , 4 , 14 , 17 , 19 , 23 , 24 , 25 , 26 , 27 , 28 ].…”

Low-temperature large-area fabrication of ZnO nanowires on flexible plastic substrates by solution-processible metal-seeded hydrothermal growth

“…Possessing wide band gap (~ 3.37 eV), large exciton binding energy (~ 60 meV), non-central symmetric wurtzite crystal structure (a = 0.3249 nm, c = 0.5205 nm), and biocompatibility, zinc oxide (ZnO) has been one of the most versatile metal oxide materials [1,2]. ZnO and its microand nanostructures have accordingly enabled many diverse functional devices covering electronics, photonics, transducers, bioengineering, and so on [3][4][5][6][7][8]. While a variety of nanoscale configurations are available for ZnO, one-dimensional (1D) nanowires (NWs) may be particularly useful and available for most of the practical applications because of their structural simplicity and growth controllability [2,[9][10][11].…”