Origin of Anomalous Piezoresistive Effects in VLS Grown Si Nanowires

Abstract

Although the various effects of strain on silicon are subject of intensive research since the 1950s the physical background of anomalous piezoresistive effects in Si nanowires (NWs) is still under debate. Recent investigations concur in that due to the high surface-to-volume ratio extrinsic surface related effects superimpose the intrinsic piezoresistive properties of nanostructures. To clarify this interplay of piezoresistive effects and stress related surface potential modifications, we explored a particular tensile straining device (TSD) with a monolithic embedded vapor–liquid–solid (VLS) grown Si NW. Integrating the suspended NW in a gate all around (GAA) field effect transistor (FET) configuration with a transparent gate stack enables optical and field modulated electrical characterization under high uniaxial tensile strain applied along the ⟨111⟩ Si NW growth direction. A model based on stress-induced carrier mobility change and surface charge modulation is proposed to interpret the actual piezoresistive behavior of Si NWs. By controlling the nature and density of surface states via passivation the “true” piezoresistance of the NWs is found to be comparable with that of bulk Si. This demonstrates the indispensability of application-specific NW surface conditioning and the modulation capability of Si NWs properties for sensor applications.

Vapour–liquid–solid growth of one-dimensional In2Se3 nanostructures and their promising field emission behaviour

“…We have measured the temperatures at different position in the quartz tube with respect to the source location and the temperature-position plot is depicted in figure 5. The synthesis was carried out by placing 30 the substrates at 22,20,18,16,14,12,10,7,3 position ~ 12 cm), formation of very fine ultra long In 2 Se 3 nanowires is observed (Fig. (g), Scheme: 2).…”

“…[1][2][3][4][5][6] The physico-chemical properties of these inorganic semiconductor chalcogenides can be tailored via shape and size control. Furthermore, they are expected to play important role as both interconnects and the key units of 25 next-generation nanoscale electronic, and optoelectronic devices.…”

“…Furthermore, systematic studies pertaining to synthesis of In 2 Se 3 nanostructures employing a single step facile route (like thermal 50 evaporation) are desirable; as such studies are scientifically as well as technologically meaningful and significantly contribute to the existing knowledge in this field.With the advent of nanotechnology, various researchers have reported synthesis and optoelectronic properties of different nano-forms of In 2 Se 3 , such 55 as nanowires, nanotrees, nanobelts, and nanoflakes and its potential applications. [1][2][3][4][5][6][7][8][9][10][11] In this regard, Q. L. Li et.al have synthesized single crystalline In 2 Se 3 nanowires array using horizontal tube furnace under controlled ambient of a mixture of Ar and H 2 gases at high temperature. The authors have explored 60 the potential of nanowires as visible light photo-detector.…”

Tuning piezoresistive transduction in nanomechanical resonators by geometrical asymmetries

“…Electrical transduction can be implemented, for example, by capacitive, 5 piezo-electric, 6 or piezo-resistive 7 read-out. Compared to other methods, piezoresistive read-out presents the advantage of easy implementation, since the beam itself acts as a piezoresistive gauge, simplifying device design and fabrication.While the so called giant piezoresistance effect has enabled piezoresistive read-out in DCB silicon nanowires fabricated by bottom-up methods, 8,9 it has not been observed in top-down fabricated DCBs. Recently, it has been shown that geometrical asymmetries present in DCBs cause an enhancement of the piezoresistive transduction, allowing to obtain large read-out electrical signals from silicon nanowire resonators obtained by top-down and bottom-up fabrication methods.…”

“…While the so called giant piezoresistance effect has enabled piezoresistive read-out in DCB silicon nanowires fabricated by bottom-up methods, 8,9 it has not been observed in top-down fabricated DCBs. Recently, it has been shown that geometrical asymmetries present in DCBs cause an enhancement of the piezoresistive transduction, allowing to obtain large read-out electrical signals from silicon nanowire resonators obtained by top-down and bottom-up fabrication methods.…”