The complete Raman spectrum of SnO2 nanoparticles in presented and analyzed. In addition to the “classical” modes observed in the rutile structure, two other regions shown Raman activity for nanoparticles. The Raman bands in the low-frequency region are attributed to acoustic modes associated with the vibration of the individual nanoparticle as a whole. The high-frequency region is activated by surface disorder. A detailed analysis of these regions and the changes in the normal modes of SnO2 are presented as a function nanoparticle size.

Dissipated power in metal oxide nanowires $\left(r_{\text{NW}}<45\text{nm}\right)$ often causes important self-heating effects and as a result, undesired aging and failure of the devices. Nevertheless, this effect can be used to optimize the sensing conditions for the detection of various gaseous species, avoiding the requirement of external heaters. In this letter, the sensing capabilities of self-heated individual ${\text{SnO}}_2$ nanowires toward ${\text{NO}}_2$ are presented. These proof-of-concept systems exhibited responses nearly identical to those obtained with integrated microheaters, demonstrating the feasibility of taking advantage of self-heating in nanowires to develop ultralow power consumption integrated devices.