Indium nitride from indium iodide at low temperatures: synthesis and their optical properties

Abstract

In this paper, we present an effective synthetic protocol to produce high quality InN nanocrystals using indium iodide (InI 3 ), one member of the family of indium halides, as the indium source at a low temperature of o250 1C (far below the decomposition temperature of InN). Notably, reports on InN synthesized from indium halides are rare due to the lack of well-defined synthetic protocols. Here, indium iodide (InI 3 ), with a stronger covalent ability, can also prevent the In 31 from being reduced to elemental indium, and then InN is formed. This synthetic protocol not only provides an alternative method to successfully synthesize highquality InN, but is also useful to fabricate other functional materials by using stronger covalent reactants to prevent reduction/oxidation in the oxidation/reduction reaction process, respectively. Furthermore, we also report the first example of an orientation-attachment process occurring between the metal nitride particles. The high purity of the InN nanoparticles can be seen from the XPS and HRTEM results, showing the asobtained products possess no obvious iodine or amorphous layers on the surface of particles, respectively. By controlling the parameters of reaction temperature and time, nanoparticles with different sizes were obtained as the final products. Raman and IR results indicate that our experimental data were consistent with the theoretical prediction and this gives further evidence that high quality InN nanocrystals were obtained. Moreover, it has been shown that the near-infrared band around 0.7 eV is characteristic of these samples and there were no obvious peaks around 1.9 eV, indicating that these InN nanocrystals exhibit a band gap of 0.7 eV, rather than the previously accepted 1.9 eV.

Control of Plasmonic and Interband Transitions in Colloidal Indium Nitride Nanocrystals

“…In addition, both EA and XPS analyses are consistent with respect to excess metal content, a phenomenon commonly found in colloidally grown, binary semiconductor NCs such as CdSe, 49 PbSe, 50 and InN. 21,24,26 Whereas the photophysics of metal chalcogenide NCs may be tuned by varying the stoichiometry at the NC surface, 51−53 this strategy has not been demonstrated for InN NCs. Modifying the chemical composition of these metal-rich InN NCs via surface chemistry modification may afford another avenue to tune the optical properties of this material.…”

Ambient pressure, low-temperature synthesis and characterization of colloidal InN nanocrystals

“…6 In addition, it is of interest to understand how defining characteristics, such as polarization, are manifested at the nanoscale. While several groups have grown InN nanoparticles through solvothermal autoclave methods, 7,8 ammonolysis, 9 thermal decomposition of indium– urea complexes, 10,11 or solid-state metathesis reactions, 12 the results were typically large agglomerations of nanocrystalline InN with no reports of high-yield colloidal solubility in organic or aqueous solvents.…”

“…Our relative peak areas are similar to two previous reports, though it is unknown whether those reports used a standard to calibrate their quantitative results. 7,16 …”

Synthesis of InN nanoparticles by rapid thermal ammonolysis

“…Even though these techniques utilize very sophisticated equipment, many difficulties have not yet been overcome due to the low decomposition temperature of InN. Recent works published on the synthesis of InN nanoparticles are based on solvothermal methods at elevated pressure and temperatures (Wu et al 2005;Xiao et al 2003), metathesis reactions (Bai et al 2002), decomposition of nitrogen-containing indium compounds (Schofield et al 2004), or reactions of sodium amide with indium halogenide at elevated temperatures (Hsieh et al 2010). The synthesis of InN nanostructures using indium oxide ammonolysis has also been reported (Schwenzer et al 2004).…”