摘要
为了改善本征石墨烯基电阻型气体传感器的室温气体响应性能,采用电子束蒸镀方法在原器件沟道区域分别沉积六种超薄金属,包括1 nm的Au、Ag、Pt、Pd、Ti和Al,并检测这些器件对NO_2和NH_3气体的响应特性。发现修饰有1 nm Pt的器件对通入3 min 3×10~(-6) NO_2气体有最高的响应灵敏度,达-56.6%,比原石墨烯器件提高了约9.3倍,但该器件响应饱和较早。而修饰有1 nm Ti的器件对NO_2气体的响应在灵敏度、恢复性等方面都有较好改善,且对NO_2气体浓度有最佳的线性响应,表现出较大的动态探测范围。然而除1 nm Ti以外,修饰有其他五种金属的石墨烯对400×10~(-6) NH_3的响应均没有明显改善。文章对不同金属材料修饰导致器件气体敏感性能差异的原因进行了分析与讨论。
In order to improve the room temperature(RT)properties of pristine graphene-based resistor-type gas sensor,six kinds of ultrathin metals,including 1 nm Au,Ag,Ti,Al,Pt and Pd,was deposited respectively on the channel of graphene device by electron beam evaporation,and their response performances were test when exposed to NO_2 and NH_3. The Pt decorated device had the largest sensitivity as-56.6% upon exposure to 3×10~(-6) NO_2 for 3 minutes at RT,which was 9.3 times more than that of pristine graphene device. But the sensitivity saturation of this device occurred relatively early. The Ti decorated device not only exhibited good sensitivity and recovery performance but also the best linear response to NO_2 concentrations,which suggests a large dynamic detection range. But except for device decorated with 1 nm Ti,there were no obvious improvements for other devices on exposure to 400×10~(-6) NH_3. The reasons of different responses caused by different metal materials modification are also analyzed and discussed.
引文
[1] Rumyantsev S,Lui G,Shur M S,et al.Selective Gas Sensing with a Single Pristine Graphene Transistor[J].Nano Lett,2012,12(5):2294-2298.
[2] Bolotin K L,Sikes K J,Jiang Z,et al.Ultrahigh Electron Mobility in Suspended Graphene[J].Solid State Commun,2008,146(9-10):351-355.
[3] Morozov S V,Novoselov K S,Katsnelson M I,et al.Giant Intrinsic Carrier Mobilities in Graphene and Its Bilayer[J].Phys Rev Lett,2008,100(1):016602(1-4).
[4] Schedin F,Geim A K,Morozov S V,et al.Detection of Individual Gas Molecules Absorbed on Graphene[J].Nature Materials,2007,6(9):652-655.
[5] Byungjin Cho,Jongwon Yoon,Myung Gwan Hahm,et al.Graphene-Based Gas Sensor:Metal Decoration Effect and Application to a Flexible Device[J].J Mater Chem C,2014,27(2):5280-5285.
[6] Chen X,Zhang L,Chen S.Large Area CVD Growth of Graphene[J].Synthetic Metals,2015,210(7):95-108.
[7] Vasic B,Zurutuza A,Gajic R.Spatial Variation of Wear and Electrical Properties Across Wrinkles in Chemical Vapour Deposition Graphene[J].Carbon,2016,102(2):304-310.
[8] Tyurnina A V,Okuno H,Pochet P,et al.CVD Graphene Recrystallization as a New Route to Tune Graphene Structure and Properties[J].Carbon,2016,102(2):499-505.
[9] Kaindl R,Jakopic G,Resel R,et al.Synthesis of Graphene Layer Nanosheet Coatings by PECVD[J].Mater Today:Proceed,2015,2(8):4247-4255.
[10] 李辉,高致慧,林伟豪,等.石墨烯气体传感解吸附特性研究[J].传感技术学报,2016,29(7):990-993.
[11] Li X,Cai W,An J,et al.Large-Area Synthesis of High-Quality and Uniform Graphene Films on Copper Foils[J].Science,2009,324(5932),1312-1314.
[12] Zhang Y,Franklin N W,Chen R J,et al.Metal Coating on Suspended Carbon Nanotubes and Its Implication to Metal-Tube Interaction[J].Chem Phys Lett,2000,331(1),35-41.
[13] Jung I,Dikin D A,Piner R D,et al.Tunable Electrical Conductivity of Individual Graphene Oxide Sheets Reduced at“low”Temperatures[J].Nano Lett,2008,8:4283-4287.
[14] Zhou M,Lu Y H,Cai Y Q,et al.Adsorption of Gas Molecules on Transition Metal Embedded Graphene a Search for High-Performance Graphene-Based Catalysts and Gas Sensors[J].Nanotechnology,2011,22(38):385502(1-8).
[15] 李金兵,姜志全,黄伟新.NO2在Ag/Pt(110)双金属表面上的吸附和分解[J].物理化学学报,2013,29(4):837-842.
[16] Yoo E,Okata T,Akita T,et al.Enhanced Electrocatalytic Activity of Pt Subnanoclusters on Graphene Nanosheet Surface[J].Nano Letters,2009,9(6),2255-2259.
[17] Wang Q J,Che J G.Origins of Distinctly Different Behaviors of Pd and Pt Contacts on Graphene[J].Phys Rev Lett,2009,103(6):066802(1-8).赵珉(1975-),女,副教授,博士,主要从事微纳加工、微纳器件及传感器件研究,zhaom@lingnan.edu.cn。
