Infrared lasing from single-crystalline InN nanobelts grown by metal organic chemical vapor deposition was demonstrated. Transmission electron microscopy studies revealed that the InN nanobelts of rectangular cross section grew along ͓110͔ direction and were enclosed by ±͑001͒ and ±͑110͒ planes. The infrared lasing action was observed at 20 K in the InN nanobelts grown on an amorphous silicon nitride coated silicon substrate by continuous wave laser pumping.

In the past few years InN, the least understood Group III nitride compound, has attracted a great deal of interest because of its unique properties, making it suitable for applications in various electronic and optoelectronic devices. [1][2][3][4][5][6][7][8] In addition, InN is considered as a potential material for lowcost, low-power-consumption, high-sensitivity detection in gas, vapors, and liquids by virtue of its intrinsic surface charge accumulation. [9][10][11][12] Consequently, the preparation and study of InN nanomaterials are of particular importance in the aforementioned devices owing to the high surface-to-volume ratio as compared to the bulk, a property which may largely enhance the operation efficiency. One-dimensional (1D) nanostructures are excellent systems in which one can investigate the dependence of their unique fundamental properties on dimensionality and their potential applications. [13][14][15][16][17] Recently, it has been demonstrated that wurtzite nanobelts have the potential of converting biological mechanical energy, vibration energy, and biofluid hydraulic energy into electricity, raising the tantalizing prospect of the self-powering of wireless nanodevices and nanosystems for optoelectronics, biosensors, and resonators.[18] Therefore, InN nanobelts are promising candidates for incorporation into the above-mentioned devices. Despite all these potential advantages of InN nanobelts studies on this material remain scarce, most probably because of the difficulties associated with the growth of belt-like nanostructures. In this Communication, we have discovered several unique behaviors based on the study of photoluminescence (PL) and Raman scattering spectra of high-quality InN nanobelts fabricated by the metal-organic chemical vapor deposition (MOCVD) technique. The PL spectra of these InN nanobelts exhibit an extraordinarily large blue-shift with increasing excitation intensity, as compared with their thin-film counterparts. In addition, we found that the phonon frequencies of InN nanobelts decrease with increasing excitation intensity. Surface band bending, piezoelectricity, and photoelastic effects were employed to explain these anomalous behaviors. Besides, temperature-dependent PL spectra are also consistent with the prediction of our proposed model. Structural and morphological information of the as-synthesized InN nanobelts was obtained from scanning electron microscopy (SEM) images. Apparently, high-density belt-like structures with length of several tens of nanometers cover the substrate, as shown in Figure 1. A high-magnification SEM image (inset to Fig. 1) revealed that the morphologies of the nanobelts are well-faceted with smooth surfaces. A detailed examination of the nanobelts along their length showed that they were uniform in both width and thickness, ranging from 40 to 250 nm and 10 to 35 nm, respectively.Typical PL spectra of the nanobelts measured at 20 K under different excitation intensities are shown in Figure 2a. A strong PL emission at 0.82 eV and blue-shifts o...