{"id":1817,"date":"2010-07-13T11:58:09","date_gmt":"2010-07-13T15:58:09","guid":{"rendered":"https:\/\/wpmu2.mit.local\/?p=1817"},"modified":"2010-07-13T11:58:09","modified_gmt":"2010-07-13T15:58:09","slug":"carbon-nanotube-based-piezoresistive-mems-sensors","status":"publish","type":"post","link":"https:\/\/wpmu2.mit.local\/carbon-nanotube-based-piezoresistive-mems-sensors\/","title":{"rendered":"Carbon Nanotube-based Piezoresistive MEMS Sensors"},"content":{"rendered":"<div class=\"page-restrict-output\"><p>Due to their inherently small size and their high sensitivity to strain, carbon nanotube (CNT) based sensors offer the potential to overcome some of the current limitations in MEMS\/NEMS sensing applications.\u00a0\u00a0 However, a better understanding of what causes this high strain sensitivity is needed to design and manufacture high-performance sensor systems.\u00a0 A MEMS test structure was designed and microfabricated in order to measure the CNT gauge factor.\u00a0 As Figure 1 shows, this test structure consists of a fixed-fixed flexure beam with electrodes connected to the base of the flexure.\u00a0 The outer four sets of electrodes are connected to polysilicon piezoresistors while the inner two electrodes are left empty so that CNTs can be connected across them.\u00a0 These central electrodes are spaced 1\u03bcm apart.\u00a0 This architecture allows the strain in the flexure to be measured simultaneously by both the polysilicon and CNT piezoresistors. The center of the flexure has a locating hole where weights can be placed to load the structure and strain the CNTs. The CNTs are deposited onto these test flexures using dielectrophoresis.\u00a0 A low-noise-sensor system was setup to measure the gauge factor of the CNT resistor network.\u00a0 The CNT resistor network was incorporated into a DC Wheatstone bridge in a quarter bridge configuration. Using this setup, the gauge factor of the CNT resistor network was measured to be 73 9, as Figure 2 shows.\u00a0 The experimental measurement of the gauge factor of the CNT resistor network is within experimental error of the theoretical gauge factor of a CNT resistor network composed of randomly selected CNTs.<\/p>\n\n\t\t<style type=\"text\/css\">\n\t\t\t#gallery-1 {\n\t\t\t\tmargin: auto;\n\t\t\t}\n\t\t\t#gallery-1 .gallery-item {\n\t\t\t\tfloat: left;\n\t\t\t\tmargin-top: 10px;\n\t\t\t\ttext-align: center;\n\t\t\t\twidth: 50%;\n\t\t\t}\n\t\t\t#gallery-1 img {\n\t\t\t\tborder: 2px solid #cfcfcf;\n\t\t\t}\n\t\t\t#gallery-1 .gallery-caption {\n\t\t\t\tmargin-left: 0;\n\t\t\t}\n\t\t\t\/* see gallery_shortcode() in wp-includes\/media.php *\/\n\t\t<\/style>\n\t\t<div id='gallery-1' class='gallery galleryid-1817 gallery-columns-2 gallery-size-medium'><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/wpmu2.mit.local\/wp-content\/uploads\/2010\/07\/cullinan_piezoresistor01.jpg'><img width=\"300\" height=\"261\" src=\"https:\/\/wpmu2.mit.local\/wp-content\/uploads\/2010\/07\/cullinan_piezoresistor01-300x261.jpg\" class=\"attachment-medium size-medium\" alt=\"Figure 1\" loading=\"lazy\" aria-describedby=\"gallery-1-1818\" srcset=\"https:\/\/wpmu2.mit.local\/wp-content\/uploads\/2010\/07\/cullinan_piezoresistor01-300x261.jpg 300w, https:\/\/wpmu2.mit.local\/wp-content\/uploads\/2010\/07\/cullinan_piezoresistor01.jpg 339w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-1818'>\n\t\t\t\tFigure 1: CNT resistor network between two electrodes on the test structure.\n\t\t\t\t<\/dd><\/dl><dl class='gallery-item'>\n\t\t\t<dt class='gallery-icon landscape'>\n\t\t\t\t<a href='https:\/\/wpmu2.mit.local\/wp-content\/uploads\/2010\/07\/cullinan_piezoresistor02.jpg'><img width=\"300\" height=\"153\" src=\"https:\/\/wpmu2.mit.local\/wp-content\/uploads\/2010\/07\/cullinan_piezoresistor02-300x153.jpg\" class=\"attachment-medium size-medium\" alt=\"Figure 2\" loading=\"lazy\" aria-describedby=\"gallery-1-1819\" srcset=\"https:\/\/wpmu2.mit.local\/wp-content\/uploads\/2010\/07\/cullinan_piezoresistor02-300x153.jpg 300w, https:\/\/wpmu2.mit.local\/wp-content\/uploads\/2010\/07\/cullinan_piezoresistor02.jpg 339w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/a>\n\t\t\t<\/dt>\n\t\t\t\t<dd class='wp-caption-text gallery-caption' id='gallery-1-1819'>\n\t\t\t\tFigure 2: Measured change in resistance vs. strain for a CNT parallel-resistor network.\n\t\t\t\t<\/dd><\/dl><br style=\"clear: both\" \/>\n\t\t<\/div>\n\n<\/div>","protected":false},"excerpt":{"rendered":"<div class=\"page-restrict-output\"><p>Due to their inherently small size and their high sensitivity to strain, carbon nanotube (CNT) based sensors offer the potential&#8230;<\/p>\n<\/div>","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[11],"tags":[4188,4200],"_links":{"self":[{"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/posts\/1817"}],"collection":[{"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/comments?post=1817"}],"version-history":[{"count":3,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/posts\/1817\/revisions"}],"predecessor-version":[{"id":1822,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/posts\/1817\/revisions\/1822"}],"wp:attachment":[{"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/media?parent=1817"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/categories?post=1817"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpmu2.mit.local\/wp-json\/wp\/v2\/tags?post=1817"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}