Highly sensitive and selective trimethylamine sensor using one-dimensional ZnO-Cr2O3 hetero-nanostructures.
Highly selective and sensitive detection of trimethylamine (TMA) was achieved by the decoration of discrete p-type Cr(2)O(3) nanoparticles on n-type ZnO nanowire (NW) networks. Semielliptical Cr(2)O(3) nanoparticles with lateral widths of 3-8 nm were deposited on ZnO NWs by the thermal evaporation of CrCl(2) at 630 °C, while a continuous Cr(2)O(3) shell layer with a thickness of 30-40 nm was uniformly coated on ZnO NWs at 670 °C. The response (R(a)/R(g): R(a), resistance in air; R(g), resistance in gas) to 5 ppm TMA of Cr(2)O(3)-decorated ZnO NWs was 17.8 at 400 °C, which was 2.4 times higher than that to 5 ppm C(2)H(5)OH and 4.3-8.4 times higher than those to 5 ppm p-xylene, NH(3), benzene, C(3)H(8), toluene, CO, and H(2). In contrast, both pristine ZnO and ZnO (core)-Cr(2)O(3) (shell) nanocables (NCs) showed comparable responses to the different gases. The highly selective and sensitive detection of TMA that was achieved by the deposition of semielliptical Cr(2)O(3) nanoparticles on ZnO NW networks was explained by the catalytic effect of Cr(2)O(3) and the extension of the electron depletion layer via the formation of p-n junctions.
Department of Materials Science and Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713, Republic of Korea.
Hyung-Sik
HS
Woo
Chan Woong
CW
Na
Il-Doo
ID
Kim
Jong-Heun
JH
Lee
D017608:Chromium Compounds / Q000737:chemistry*; D005740:Gases / Q000032:analysis / Q000737:chemistry; D008744:Methylamines / Q000032:analysis* / Q000737:chemistry; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods; D012666:Semiconductors; D012680:Sensitivity and Specificity; D015034:Zinc Oxide / Q000737:chemistry*
D017608:Chromium Compounds; D005740:Gases; D008744:Methylamines; C023336:trimethylamine; D015034:Zinc Oxide; C023600:chromic oxide