Te Precursor Research Articles

Control of carbon content in amorphous GeTe films deposited by plasma enhanced chemical vapor deposition (PE-MOCVD) for phase-change random access memory applications

Amorphous and smooth GeTe thin films are deposited on 200 mm silicon substrates by plasma enhanced—metal organic chemical vapor deposition (PE–MOCVD) using the commercial organometallic precursors TDMAGe and DIPTe as Ge and Te precursors, respectively. X-ray photoelectron spectroscopy (XPS) measurements show a stoichiometric composition of the deposited GeTe films but with high carbon contamination. Using information collected by Optical Emission Spectroscopy (OES) and XPS, the origin of carbon contamination is determined and the dissociation mechanisms of Ge and Te precursors in H2 + Ar plasma are proposed. As a result, carbon level is properly controlled by varying operating parameters such as plasma radio frequency power, pressure and H2 rate. Finally, GeTe films with carbon level as low as 5 at. % are obtained.

Soft chemistry synthesis route toward Bi2Te3 hierarchical hollow spheres

Hollow spheres made of Bi2Te3 nanoplatelets were successfully synthesized using a low temperature, wet chemical synthesis route. By using a one-pot synthesis, large quantities of microspheres, arranged in a gypsum flower manner, can be obtained in about 1 h. The mechanism leading to such a particular morphology has been deeply studied by both solid and solution characterization techniques (X-ray diffraction, scanning and transmission electron microscopy, X-ray fluorescence, 1H nuclear magnetic resonance spectroscopy) which were carried out at different stages of the synthesis. The key points are the generation of alcanethiol-in-polyol droplets and the subsequent in situ controlled interfacial reaction between Te and Bi precursors. The Te(IV) ions present in the alcanethiol phase are initially reduced into Te(0) by decanethiol. The Bi(III) ions initially dissolved in the polyol phase are then reduced at the decanethiol/polyol interface, resulting in the progressive growth of Bi2Te3 hexagonal nanoplatelets at the outer surface of the pristine Te(0) sphere.

Aberration Corrected STEM Study of the Surface of Lead Chalcogenide Nanoparticles

In this contribution, we report on the microscopic and spectroscopic characterization of lead chalcogenide nanoparticles. PbSe and PbTe nanoparticles were synthesized by chemical methods, using different molar ratios of Pb, Se, and Te precursors and varying the reaction time. These nanoparticles were characterized by means of transmission electron microscopy and their related techniques: electron diffraction, energy dispersive X-ray spectroscopy (EDXS), electron energy loss spectroscopy (EELS), and aberration corrected scanning transmission electron microscopy (AC-STEM), to obtain information related to their morphology, crystal structure, and composition. They were also characterized by means of Fourier transform infrared (FTIR) absorption spectroscopy to assess the functional groups found on the surface of the nanoparticles, depending on the synthesis conditions. The results obtained showed that the synthesized nanoparticles always display a higher concentration of Pb compared to that of the chalcogen. ...

Self-assembly of nanoparticles to form tree-like tellurium nanostructures using novel starting reagents

A new rapid and single step thermal method was successfully developed to synthesize tree-like tellurium (Te) nanostructures at mild condition. Te nanostructures were synthesized using tellurium tetrachloride (TeCl4) as a Te precursor and thioglycolic acid (TGA) as reducing and caping agent. No secondary chemical reducing agent is required to proceed and complete the reaction. A preliminary study on the possibility of developing a solar cell having the fluorine-doped tin oxide (FTO)/TiO2/Te/Pt–FTO structure was also investigated to produce an inexpensive solar cell by Te nanostructures.

Water Soluble CdTe Quantum Dots for Mercury Detection

Nanomaterials are becoming one of the most important classes of material research [1]. For example, quantum dots (QDs), especially water soluble QDs, have been used in many areas of research [2-3]. QDs are nanosize crystals of inorganic semiconductors with diameter in the range of 1-10 nm [4]. At such small sizes (close to or smaller than the dimensions of the exciton Bohr radius within the corresponding bulk material), these nanostructured materials behave differently from bulk solids, because of quantum-confinement effects [4]. As a result of quantum-confinement, they have unique optical and electronic properties such as broad excitation spectra and narrow, symmetric and tunable emission spectra [4]. Therefore, QDs have been used as novel luminescent sensors for chemical and biological species [5-8].This study fabricated cadmium telluride (CdTe) QDs from aqueous solution containing CdCl2 and Te precursor in presence of thioglycolic acid. The resulted QDs were characterized by using Uv-Vis. spectroscopy, photoluminescence (PL) spectroscopy and transmission electron microscopy (TEM). The results demonstrated that low concentration, in nano-molar range, of Hg(II) ions could effectively quench the CdTe QDs fluorescence because Hg(II) ions form a stable complex with QDs coating (thioglycolic acid) which allow for an effective electron transfer from the QDs to the Hg(II). A linear response to Hg(II) ions in the concentration range from 0.625 to 8.0 n M was observed and the detection limit of this sensor was 0.625 nM and sensitivity was equal to 53.4 /nM. References Rosi NL, Mirkin CA Nanostructures in biodiagnostics. Chem Rev 105:1547–1562 (2005)Goldman ER, Balighian ED, Mattoussi H, Kuno MK, Mauro JM, Tran PT, Anderson GP (2002) Avidin: a natural bridge for quantum dot-antibody conjugates. J Am Chem Soc 124:6378–6382Chen Y, Rosenzweig Z (2002) Luminescent CdS quantum dots as selective ion probes. Anal Chem 74:5132–5138Alivisatos AP (1996) Perspectives on the physical chemistry of semiconductor nanocrystals. J Phys Chem 100:13226–13239Chan WCW, Maxwel DJ, Gao X, Bailey RE, Han M, Nie S (2002) Luminescent quantum dots for multiplexed biological detection and imaging. Curr Opin Biotechnol 13:40–46Zhang L, Ci Xu, Li B (2009) Simple and sensitive detection method for chromium(VI) in water using glutathione—capped CdTe quantum dots as fluorescent probes. Microchim Acta 166: 61–68Landes C, Burda C, Braun M, El-Sayed MA (2001) Photoluminescence of CdSe nanoparticles in the presence of a hole acceptor: n-Butylamine. J Phys Chem B 105:2981–2986Dong F, Hu K, Han H, Liang J (2009) A novel method for methimazole determination using CdSe quantum dots as fluorescence probes. Microchim Acta 165:195–201

Reason and Role of Atomic Layer Deposition for PCRAM and ReRAM Films

With a 13.4% CAGR, the demand for diverse memory applications in mobile phones, digital cameras, MP3 players, video game consoles and automobiles are exploding rapidly. To keep up with the diverse applications of memory devices, a number of next generation memory options are being studied, such as STTRAM, PCRAM and ReRAM. Most promising solutions for future non-volatile memories replacing conventional NAND are Phase Change Memory (PCRAM) and Resistive Memory (ReRAM). The growth of complex thin films through atomic layer deposition (ALD) is finding a broad range of applications for the production of next-generation memory devices. Conformal coating or gap-fill of high-quality thin films helps to mitigate multiple technology challenges encountered in new material development for high aspect ratio device structures. Similar step-coverage and composition controls are needed for fabricating next-generation non-volatile memory devices including phase-change memory (PCRAM) and resistive memory (ReRAM). This presentation will introduce a multi-wafers ALD system, QXP-8300 equipped with liquid injection vaporizers integrated with close-coupled showerhead in a small volume confined process space. This paper will also discuss recent new developments in equipment design to meet the technology needs as well as practical manufacturing targets (such as throughput and cost of ownership) in order to provide a production-worthy ALD solution. Applications in new memories such as PCRAM materials (such asGST), and O-vacancy controlled ReRAM materials will be reviewed. The formation of such engineered materials often requires chemical precursors that are low vapor-pressure liquids or even solids, posing a significant engineering challenge for production equipment design. With the help of thermal and flow modelling, designs are optimized for precursor evaporation, vapour delivery, and reactor geometry in order to maximize step-coverage and minimize ALD cycle time. Innovative platform architecture further improves system productivity, reduces defects, and enhances overall system cost of ownership. Results on both unit process and electrical characteristics will be presented for multiple ALD films generated from such a high-volume production system. Among the various candidate PCRAM alloys, GexSbyTez (GST) is the most promising because of its good scalability, low cost, and compatibility with conventional CMOS process. Conventional PCRAM had been researched and developed using physical vapour deposition. As devices scale down to 20 nm and beyond, confined and conformal GST film deposition into hole/trench structures is required, using ALD processes. However, to ensure good gapfill in a sub-20nm structures by ALD process, choice of precursors and precursors’ delivery challenges are far greater and require unique precursor delivery methodology to ensure good void-free gapfill while maintaining higher productivity. This paper highlights the progress made in ALD equipment development offering solutions for critical problems facing sub 20nm ALD PCRAM technology nodes. Using vaporizers suitable for Ge, Sb and Te precursors, ALD GST films were deposited in a Multi-wafer ALD system characterized by Small volume reactor and Closely coupled showerhead process. In this presentation, results are presented showing progress in GST film deposition into sub 20nm structures. ALD GST films were deposited under process conditions which achieved void-free gap-fill. By controlling injection dose and other parameters, such as temperature, pressure, etc., GST composition can be varied from Sb rich to Te rich in the films. Electrical characterization showing reset current <150uA due to confined cell enabled by ALD will be presented in this paper. Similarly, binary films of HfO2, HfO2/TiO2 and doped HfO2 deposited by ALD process showed lower forming voltage and high resistance ratio for ReRAM application. ALD can be used not only to tailor the composition of the films, it can also be utilized to conformally deposite multi-layers binary films for 3D ReRAM cross-point structure.

ALD Synthesis of Ternary PbSeTe Layers Alternating with the Binary PbTe in Nanolaminate Structures for High Zt Thermoelectric Materials

Thermoelectric materials have attracted much attention for their potential in conversion between heat and electricity and consequently could be used for heating and cooling systems. The efficiency of a thermoelectric material is expressed by the dimensionless thermoelectric figure of merit, ZT = S2σT/ k, where S is the Seebeck coefficient, σ is the electrical conductivity, and kis the thermal conductivity [1]. Previous work demonstrated alloying was used to decrease the lattice thermal conductivity and thus to increase ZT owning to mass difference enhanced phonon scattering. In order to further progress in the development and commercialization of the next generation of thermoelectric devices it is necessary to enhance the ZT value. Most recently research focused on low dimensional nanostructures, including quantum wells, quantum dots, superlattice, quantum wires and nanolaminates to improve ZT. In superlattice structures, reduced lattice thermal conductivity is mainly due to the phonon scattering at multiple interface boundaries. Significant efforts have been made to investigate the IV-VI semiconducting lead chalcogenides, such as PbTe and PbSe due to their high figure of merit, good chemical stability, low vapor pressure and high melting point. Therefore they are promising thermoelectric materials for intermediate temperature applications ranging from 600 to 800 K.PbTe and PbSe films have been deposited by different techniques, such as pulsed laser deposition (PLD), metal-organic chemical vapor deposition (MO-CVD), magnetron sputtering, molecular beam epitaxy (MBE) and atomic layer deposition (ALD). Among these, ALD is considered as a novel and competitive method to deposit PbTe/PbSe nanolaminate structures. The ALD is a self-limiting atomic layer reaction in each ALD cycle introduce. It can precisely control the film layer thickness, stoichiometry, composition, uniformity, and sharp interface. ALD also can be used to deposit conformal films onto very complex structures. It is possible to generate the reproducible and well-defined nanolaminate structures. Furthermore, the deposition temperature of ALD is rather low in comparison with other growth techniques.In this work we report on the successful synthesis of multiple PbTe/PbSeTe nanolaminates on silicon substrates by a thermal ALD system. In this new nanolaminate structure a very thin layer of the PbSeTe ternary compound is formed by nucleation of PbSe quantum dots between binary PbTe layers, which is followed by an annealing process step. It is noted that the formation of the PbSe quantum dots is facilitated the prevailing Volmer-Weber island growth mode. Lead bis(2,2,6,6-tetramethyl-3,5-heptanedionato) (Pb(C11H19O2)2), (trimethylsilyl) telluride ((Me3Si)2Te) and (trimethylsilyl) selenide ((Me3Si)2Se) were employed as the chemical ALD precursors for lead, telluride and selenide, respectively. 20 sccm N2 was used as a carrier gas to transport the chemical precursors into the ALD reaction chamber. The ALD growth temperature was 170 oC. The solid lead precursor was volatilized at a temperature of 140 oC, the liquid Te precursor required heating to 40 oC, and the liquid Se precursor was kept at room temperature. The chamber base pressure was kept at 30 mTorr.Several physical characterization techniques have been employed to determine the ALD nanolaminate formation. The crystal structure was analyzed by X-ray diffraction (XRD). The film morphology and structure of the products were determined by field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HR-TEM).The surface roughness was analyzed by atomic force microscopy (AFM). The analysis of the composition and stoichiometry of the ternary and binary layers were carried out by X-ray photoelectron spectroscopy (XPS) and Energy dispersive X-ray spectroscopy (EDS).

Aqueous synthesis of luminescent cadmium telluride quantum dots using ascorbic acid as the reducing agent

A facile method for the synthesis of highly luminescent cadmium telluride (CdTe) quantum dots (QDs) in an aqueous solution is presented. Ascorbic acid and sodium tellurite were used as the reducing agent and tellurium source, respectively, to synthesise CdTe QDs under mild conditions. In this method, the preparation of the Te precursor and the growth of CdTe QDs were achieved with a one-step synthetic route. CdTe QDs with five different emission wavelengths of 506, 517, 541, 564 and 575 nm were obtained by tuning the refluxing time. The quantum yields of these QDs were 5.4, 10.9, 37.4, 53.3 and 40.1%, respectively. The X-ray powder diffraction and transmission electron microscopy characterisation indicated that the obtained QDs had a pure cubic zinc blended structure with spherical shape. The main advantage of the present method is that both the reducing agent and tellurium precursor are stable and cheap. Furthermore, no toxic gases are released in the preparation process. It is a low cost and green method suitable for large-scale synthesis.

Electrodeposition of stoichiometric bismuth telluride Bi2Te3 using a piperidinium ionic liquid binary mixture

In this paper, we report the electrodeposition of stoichiometric Bi2Te3 compound using an ionic liquid binary mixture: 1-ethyl-1-octyl-piperidinium bis(trifluoromethylsulfonyl)imide: 1-ethyl-1-octyl-piperidinium bromide (EOPipTFSI:EOPipBr 95:5 (mol%)). The use of this mixture allows to reach a higher solubility of Bi(III) and Te(IV) precursors compared to pure EOPipTFSI ionic liquid in which Te(IV) salts are not soluble. Moreover, this electrolyte presents an extended cathodic stability, allowing the study of electrochemical processes that occur at high cathodic potential values. A detailed voltammetric study of electrochemical systems was performed for electrolytes containing different [Bi(III)]/[Te(IV)] ratio, allowing the attribution of cathodic signals to electrochemical processes. Experimental conditions leading to the deposition of stoichiometric Bi2Te3 were then determined by varying deposition potential and electrolyte composition, using potentiostatic experiments followed by XRD and SEM-EDX analysis. By varying the concentration of precursors in the electrolyte, mirror-like coatings, adherent and homogeneous, were obtained. Electroplated Bi2Te3 presents n-type conductivity with a Seebeck coefficient equal to −70μVK−1 and an electrical resistivity of 133μΩm.

Facile dissolution of selenium and tellurium in a thiol–amine solvent mixture under ambient conditions

Despite their extremely low solubility in most solvents, hexagonal grey selenium and tellurium are shown to be remarkably soluble in binary mixtures of thiols and ethylenediamine (en) at room temperature and ambient pressure. A 1 : 4 vol/vol mixture of ethanethiol (EtSH) and en gave saturated solutions of 38 and 9.3 wt% for grey selenium and tellurium, respectively. Crystalline and phase-pure chalcogen is easily recovered from solution by drying and mild heat treatment at 250 °C (for selenium) or evaporation at room temperature (for tellurium). To demonstrate utility for these dissolved chalcogens, it was shown that elemental antimony readily reacts with the dissolved selenium to give a stable, solution processable Sb–Se precursor solution. In the same way, elemental tin reacts with the dissolved tellurium to generate a Sn–Te precursor solution. Upon solution deposition and heat treatment to 250 °C, these precursor solutions yielded crystalline Sb2Se3 and SnTe.

Effect of thioglycolic acid on the stability and photoluminescence properties of colloidal solutions of CdTe nanocrystals

We have studied the physicochemical properties of cadmium telluride nanostructures prepared by colloidal synthesis and analyzed the photoluminescence characteristics of CdTe nanocrystals stabilized with thioglycolic acid. The results demonstrate that the relationship between Cd and Te precursors and the synthesis time influence the nanocrystal size and the optical properties of the nanocrystal-based disperse system.

Solution-Based Synthesis of GeTe Octahedra at Low Temperature

GeTe octahedra were prepared by reaction of equimolar amounts of GeCl2·dioxane and Te(SiEt3)2 in oleylamine, whereas a slight excess of the Te precursor yielded GeTe octahedra decorated with elemental Te nanowires, which can be removed by washing with TOP. The mechanism of the GeTe formation is strongly influenced by the solvent. The expected elimination of Et3SiCl (dehalosilylation) only occurred in aprotic solvents, whereas Te(SiEt3)2 was found to react with primary and secondary amines with formation of silylamines. Temperature-dependent studies on the reaction in oleylamine showed that crystalline GeTe particles are formed at temperatures higher than 140 °C. XRD, SAED, and HRTEM studies proved the formation of rhombohedral GeTe nanoparticles. These findings were confirmed by a single-crystal and powder X-ray analysis. The rhombohedral structure modification was found, and the structure was solved in the acentric space group R3m.

Inhibition of Te surfactant effect on surface morphology of heavily Te-doped GaAs

The surface morphology and incorporation behavior of heavily Te-doped GaAs were studied for various growth parameters by chemical beam epitaxy (CBE). The Te precursor, DIPTe (diisopropyl telluride), acts as a volatile dopant in the growth temperature range of 475–595°C. Electrical activation of Te is increased for lower growth temperatures. The Te surfactant effect was shown to lead to three-dimensional growth, which greatly affected the resulting surface morphology. We have shown that growth parameters can be tuned to reduce the Te surfactant effect through kinetic limitation, thus obtaining improved surface morphologies.

CdTe1‐xSex/Cd0.5Zn0.5S core/shell quantum dots: core composition and property

Alloy CdTe(1-x)Se(x) quantum dots (QDs) have been fabricated by an organic route using Cd, Te and Se precursors in a mixture of trioctylamine and octadecylphosphonic acid at 280 °C. The variation of photoluminescence (PL) peak wavelength of the CdTe(1-x)Se(x) QDs compared with CdTe QDs confirmed the formation of an alloy structure. The Se component drastically affected the stability of CdTe(1-x)Se(x) QDs. A Cd0.5Zn0.5S shell coating on CdTe(1-x)Se(x) cores was carried out using oleic acid as a capping agent. CdTe(1-x)Se(x)/Cd0.5Zn0.5S core/shell QDs revealed dark red PL while a yellow PL peak was observed for the CdTe(1-x)Se(x) cores. The PL efficiency of the core/shell QDs was drastically increased (less than 1% for the cores and up to 65% for the core/shell QDs). The stability of QDs in various buffer solutions was investigated. Core/shell QDs can be used for biological applications because of their high stability, tunable PL and high PL efficiency.

Semiconducting Conjugated Polymer–Inorganic Tetrapod Nanocomposites

Cadmium telluride (CdTe) tetrapods were synthesized via multiple injections of the Te precursor by utilizing bifunctional ligands. Subsequently, tetrapod-shaped semiconducting inorganic-organic nanocomposites (i.e., P3HT-CdTe tetrapod nanocomposites) were produced by directly grafting conjugated polymer ethynyl-terminated poly(3-hexylthiophene) (i.e., P3HT-≡) onto azide-functionalized CdTe tetrapods (i.e., CdTe-N3) via a catalyst-free click chemistry. The intimate contact between P3HT and CdTe tetrapod rendered the effective dispersion of CdTe tetrapods in nanocomposites and facilitated their efficient electronic interaction. The success of coupling reaction was confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The grafting density of P3HT chains on the CdTe tetrapods was estimated by thermogravimetric analysis. The photophysical properties of P3HT-CdTe tetrapod nanocomposites were studied using UV-vis and photoluminescence spectroscopies. These intimate semiconducting conjugated polymer-tetrapod nanocomposites may offer a maximized interface between conjugated polymers and tetrapods for efficient charge separation and enhanced charge transport regardless of their orientation for potential application in hybrid solar cells with improved power conversion efficiency.

Surface characterization of GSH-CdTe quantum dots

The surface characterization of CdTe QDs synthesized by a novel procedure using glutathione (GSH), low temperatures (60–90 °C) and K2TeO3 as the –Te precursor is reported. Fluorescence of the produced QDs is stable in the pH range 6–13 and QDs inside eukaryotic cells are highly fluorescent. The surface composition of GSH-CdTe QDs with different spectroscopic properties and particle size distributions was determined by XPS. The XPS analysis indicated that the QDs are essentially CdTe, although all nanoparticles contain 12–24% of CdO (and in one case also TeO2). GSH decomposes with reaction time releasing small amounts of S−2 ions that react with Cd(Te) to yield Cd(Te)S in a smaller amount than that of CdTe. Finally, the use of QDs in fluorescence mediated immunodetection of bacterial pathogens has been evaluated.

Biparametric analyses of charge trapping in Cd0.9Zn0.1Te based virtual Frisch grid detectors

Detector grade Cd0.9Zn0.1Te (CZT) single crystals were grown from zone refined Cd, Zn, and Te (∼7 N) precursor materials, using a tellurium solvent method. Detectors with virtual Frisch grid configuration were fabricated using these crystals. I-V measurements revealed low leakage currents at room-temperature, ∼11 nA for one such detector D1 and ∼8 nA for another detector D2 at 1100 V. The spectroscopic performances of the two CZT virtual Frisch grid detectors have been evaluated and compared for high energy gamma ray detection. Detector D1 showed a well-resolved pulse-height spectrum with an energy resolution of ∼1.6% for the 662 keV gamma rays. Detector D2 also showed a distinct 662 keV peak but with a broader pulse-height distribution. A digital biparametric correlation study of the depth of interaction and energy deposited by the 662 keV gamma rays was carried out. A different kind of correlation pattern from that observed normally for hole trapping was noticed in the case of detector D2. Correlation of results from thermally stimulated current measurement studies suggested that the anomalous biparametric correlation pattern was due to the trapping of holes but modified by the virtual Frisch grid effect. The results also suggested that the effect of electron trapping could not be ruled out either. Finally, a digital correction scheme was applied to recover the 137Cs spectrum from the effect of charge loss.

MOCVD of C‐oriented Bi2Te3 Films on SiO2 Substrates using Triethyl Bismuth and Di‐tertiarybutyl Tellurium

AbstractMetal‐organic (MO)CVD of bismuth telluride thin films is investigated by using a combination of optimized bismuth and tellurium precursors along with H2 as a reactant gas. Good quality films are obtained, even at 300 °C. The Bi precursors are trimethyl bismuth (Bi(CH3)3, Bi(Me3)) and triethyl bismuth (Bi(C2H5)3, Bi(Et)3), and the Te precursors are diethyl tellurium (Te(C2H5)2, Te(Et)2), di‐isopropyl tellurium (Te(C3H7)2, Te(iPr)2), and di‐tertiarybutyl tellurium (Te(C4H9)2, Te(tBu)2). The integrated absorbance area of C‐H stretching vibrations in the range 2800–3200 cm−1 is estimated to determine the decomposition rate of the Bi and Te precursors. C‐oriented Bi2Te3 films are obtained at 300 °C and under 2.5 Torr using Bi(Et)3 and Te(tBu)2 and characterized. Further, the microstructure, crystallinity, and surface morphology of the films are determined. The appropriate stoichiometry of the bismuth telluride films is obtained as Bi/Te = 2:3. The combination of Bi(Et)3 and Te(tBu)2 is the most effective for low‐temperature deposition because, compared to the other precursors, the decomposition of these precursors starts at a lower temperature. Investigations of the precursor decomposition behavior show that the absorbance of C‐H stretching vibrations of ligands in precursors in the gas phase is sensitive to the analysis conditions.

Shape Control of CdTe Nanocrystals: Influence of the Solvent Composition and Ligand Effects

CdTe nanocrystals were synthesized by the hot-injection method with a mixture of oleylamine and octadecene as a solvent. The influence of the composition of the solvent and of the injection solution on the shape of CdTe nanoparticles was investigated. Various shapes of CdTe nanocrystals, such as nanodots, nanorods, multipods, and nanowires, could be obtained by changing the reaction conditions. Tuning the reactivity of both the cadmium and the tellurium precursors at the same time was found to be the main reason for the shape control of CdTe nanocrystals in this reaction system. The reactivity of the Cd precursor was controlled by the composition of the solvent, while the activity of the Te precursor could be influenced by using trioctylphosphine and tributylphosphine in the injection solution.

One-Step Hydrothermal Controlled Synthesis of HgTe Nanorods

This paper describes a one-step hydrothermal synthesis of rod-shaped HgTe nanocrystals (NCs). X-ray powder diffraction (XRD), field scanning electron microscopy (FE-SEM), transition electron microscopy (TEM) and energy-dispersive X-ray analysis (EDX) have been used to characterize the HgTe NCs. The length, diameter, surface roughness and the aspect ratio of the HgTe nanorods are well controlled through Te precursor, reaction time and reductant.