Direct Growth of Compound Semiconductor Nanowires by On-Film Formation of Nanowires: Bismuth Telluride

Abstract

Bismuth telluride (Bi(2)Te(3)) nanowires are of great interest as nanoscale building blocks for high-efficiency thermoelectric devices. Their low-dimensional character leads to an enhanced figure-of-merit (ZT), an indicator of thermoelectric efficiency. Herein, we report the invention of a direct growth method termed On-Film Formation of Nanowires (OFF-ON) for making high-quality single-crystal compound semiconductor nanowires, that is, Bi(2)Te(3), without the use of conventional templates, catalysts, or starting materials. We have used the OFF-ON technique to grow single crystal compound semiconductor Bi(2)Te(3) nanowires from sputtered BiTe films after thermal annealing at 350 degrees C. The mechanism for wire growth is stress-induced mass flow along grain boundaries in the polycrystalline film. OFF-ON is a simple but powerful method for growing perfect single-crystal compound semiconductor nanowires of high aspect ratio with high crystallinity that distinguishes it from other competitive growth approaches that have been developed to date.

Effect of growth time on structural, morphological and electrical properties of tungsten oxide nanowire

“…7a-d, in the growth mechanism of tungsten oxide nanowires, at first the tungsten substrate was oxidized and tungsten oxide-a thin film-was created on the surface of tungsten substrate and then because of the thermal expansion coefficient between the thin film and the substrate at high annealing temperature, and based on atomic diffusion enhanced by compressive stress, tungsten oxide nanowires start to grow. In fact, by atomic diffusion at grain boundaries, to release the stress, tungsten oxide nanowires are grown on the surface of the tungsten oxide thin film [26,27]. It is known that the magnitude of this stress is proportional to the growth temperature, and there exists a threshold stress level and the corresponding temperature that initiates the growth of tungsten oxide nanowires; in this case, the threshold temperature to produce sufficient compressive stress for nanowire growth is 800 °C, which according to previous studies is suitable for the growth of tungsten oxide nanowires [28,29].…”

Individual thermoelectric properties of electrodeposited bismuth telluride nanowires in polycarbonate membranes

“…Previously, significant improvements of ZT values were reported for nanostructured bulk alloys [7], nanoinclusions [8], nanocomposites [9], and thin-film superlattices [10,11]. Moreover, many different growth techniques have been explored to produce Bi 2 Te 3 materials, including vapor-phase techniques [12][13], on-film formation of nanowires (OFF-ON) [14][15][16], and electrochemical deposition [17][18][19][20][21].…”

Nanostructures of Metal Tellurides (PbTe, CdTe, CoTe2, Bi2Te3, and Cu7Te4) with Various Morphologies: A General Solvothermal Synthesis and Optical Properties

“…[2,3] Theoretical investigations suggest that Bi 2 Te 3 nanowires may exhibit ZT values much larger than 1.0, resulting from both the enhanced thermoelectric power (S) and electrical conductivity (σ) and depressed thermal conductivity (κ) in the nanostructures. [4,5] Another typical example is cadmium telluride (CdTe), a near-infrared bandgap semiconductor (E g = 1.56 eV, 300 K) with novel optical and electrical properties, having been widely used for a variety of applications such as photovoltaic devices, [6] lightemitting diodes, [7] biological sensors, [8] and nanoscale electronics. [9] In contrast to the aforementioned metal tellurides, however, fewer studies on transition metal tellurides have been performed so far.…”