http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Synthesis and Gas Sensing Properties of ZnO Nanostructures
웬래훙,안은성,정훈철,김도진,김효진 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.61
We report on the gas sensing properties of ZnO nanostructures synthesized using a simple method combined with sputtering and subsequent thermal oxidation of sputtered metallic films in dry air. By controlling the sputtering condition, we achieved polycrystalline wurtzite ZnO films with a flower-like structure consisting of nanoflakes with a thickness of ∼20 nm and a wire-like structure having a width of 100 - 150 nm and a length of several microns for deposition temperatures of room temperature and 150 ℃, respectively. From gas sensing measurements for NH3, CO, and H<SUB>2</SUB> in dry air, the gas sensors based on ZnO wire-like thin films showed quite better responses than those based on ZnO flower-like thin films. The ZnO wire-like thin film gas sensors exhibited a high sensitivity to NH3 with a maximum sensitivity as high as ∼300% for 20 ppm NH3 at an operating temperature of 200 ℃ and a detection limit of 2 ppm. In addition, the ZnO wire-like thin film gas sensors also displayed good responses to CO and H2 exposures. These results illustrate that the ZnO wire-like thin films are very promising for low-cost, high-performance gas sensors.
웬래훙,김효진,김도진,Hung, Nguyen Le,Kim, Hyo-Jin,Kim, Do-Jin 한국재료학회 2010 한국재료학회지 Vol.20 No.5
We investigated the carbon monoxide (CO) gas-sensing properties of nanostructured Al-doped zinc oxide thin films deposited on self-assembled Au nanodots (ZnO/Au thin films). The Al-doped ZnO thin film was deposited onto the structure by rf sputtering, resulting in a gas-sensing element comprising a ZnO-based active layer with an embedded Pt/Ti electrode covered by the self-assembled Au nanodots. Prior to the growth of the active ZnO layer, the Au nanodots were formed via annealing a thin Au layer with a thickness of 2 nm at a moderate temperature of $500^{\circ}C$. It was found that the ZnO/Au nanostructured thin film gas sensors showed a high maximum sensitivity to CO gas at $250^{\circ}C$ and a low CO detection limit of 5 ppm in dry air. Furthermore, the ZnO/Au thin film CO gas sensors exhibited fast response and recovery behaviors. The observed excellent CO gas-sensing properties of the nanostructured ZnO/Au thin films can be ascribed to the Au nanodots, acting as both a nucleation layer for the formation of the ZnO nanostructure and a catalyst in the CO surface reaction. These results suggest that the ZnO thin films deposited on self-assembled Au nanodots are promising for practical high-performance CO gas sensors.
웬래훙,안은성,박성용,정훈철,김효진,김도진,Nguyen, Le Hung,Ahn, Eun-Seong,Park, Seong-Yong,Jung, Hoon-Chul,Kim, Hyo-Jin,Kim, Do-Jin 한국재료학회 2009 한국재료학회지 Vol.19 No.8
ZnO wire-like thin films were synthesized through thermal oxidation of sputtered Zn metal films in dry air. Their nanostructure was confirmed by SEM, revealing a wire-like structure with a width of less than 100 nm and a length of several microns. The gas sensors using ZnO wire-like films were found to exhibit excellent $H_2$ gas sensing properties. In particular, the observed high sensitivity and fast response to $H_2$ gas at a comparatively low temperature of $200^{\circ}C$ would lead to a reduction in the optimal operating temperature of ZnO-based $H_2$ gas sensors. These features, together with the simple synthesis process, demonstrate that ZnO wire-like films are promising for fabrication of low-cost and high-performance $H_2$ gas sensors operable at low temperatures. The relationship between the sensor sensitivity and $H_2$ gas concentration suggests that the adsorbed oxygen species at the surface is $O^-$.
산화아연-탄소나노튜브 복합체의 일산화질소 가스 감지 특성에 미치는 코발트 첨가 효과
정훈철,안은성,웬래훙,오동훈,김효진,김도진,Jung, Hoon-Chul,Ahn, Eun-Seong,Hung, Nguyen Le,Oh, Dong-Hoon,Kim, Hyo-Jin,Kim, Do-Jin 한국재료학회 2009 한국재료학회지 Vol.19 No.11
We investigated the effects of Co doping on the NO gas sensing characteristics of ZnO-carbon nanotube (ZnO-CNT) layered composites fabricated by coaxial coating of single-walled CNTs with ZnO using pulsed laser deposition. Structural examinations clearly confirmed a distinct nanostructure of the CNTs coated with ZnO nanoparticles of an average diameter as small as 10 nm and showed little influence of doping 1 at.% Co into ZnO on the morphology of the ZnO-CNT composites. It was found from the gas sensing measurements that 1 at.% Co doping into ZnO gave rise to a significant improvement in the response of the ZnO-CNT composite sensor to NO gas exposure. In particular, the Co-doped ZnO-CNT composite sensor shows a highly sensitive and fast response to NO gas at relatively low temperatures and even at low NO concentrations. The observed significant improvement of the NO gas sensing properties is attributed to an increase in the specific surface area and the role as a catalyst of the doped Co elements. These results suggest that Co-doped ZnOCNT composites are suitable for use as practical high-performance NO gas sensors.
산화아연-탄소나노튜브 복합체의 일산화질소 가스 감지 특성
박성용,정훈철,안은성,웬래훙,강영진,김효진,김도진,Park, Seong-Yong,Jung, Hoon-Chul,Ahn, Eun-Seong,Nguyen, Le Hung,Kang, Youn-Jin,Kim, Hyo-Jin,Kim, Do-Jin 한국재료학회 2008 한국재료학회지 Vol.18 No.12
The NO gas sensing properties of ZnO-carbon nanotube (ZnO-CNT) composites fabricated by the coaxial coating of single-walled CNTs with ZnO were investigated using pulsed laser deposition. Upon examination, the morphology and crystallinity of the ZnO-CNT composites showed that CNTs were uniformly coated with polycrystalline ZnO with a grain size as small as 5-10 nm. Gas sensing measurements clearly indicated a remarkable enhancement of the sensitivity of ZnO-CNT composites for NO gas compared to that of ZnO films while maintaining the strong sensing stability of the composites, properties that CNT-based sensing materials do not have. The enhanced gas sensing properties of the ZnO-CNT composites are attributed to an increase in the surface adsorption area of the ZnO layer via the coating by CNTs of a high surface-to-volume ratio structure. These results suggest that the ZnO-CNT composite is a promising template for novel solid-state semiconducting gas sensors.