| DC 欄位 |
值 |
語言 |
| DC.contributor | 物理學系 | zh_TW |
| DC.creator | 洪聖均 | zh_TW |
| DC.creator | Sheng-Chun Hung | en_US |
| dc.date.accessioned | 2010-4-28T07:39:07Z | |
| dc.date.available | 2010-4-28T07:39:07Z | |
| dc.date.issued | 2010 | |
| dc.identifier.uri | http://ir.lib.ncu.edu.tw:444/thesis/view_etd.asp?URN=92242007 | |
| dc.contributor.department | 物理學系 | zh_TW |
| DC.description | 國立中央大學 | zh_TW |
| DC.description | National Central University | en_US |
| dc.description.abstract | 在本論文中，我們將討論以氮化鎵/氮化鋁鎵電晶體製作之空氣以及氯離子感應器之原理，製作，量測，以及結果討論。
在空氣感應器方面，我們以一種具有電偶極子在其結構中的高分子聚合物 : PVDF 作為閘極改質的材料。因為PVDF材料內部具有不規則排列之電偶極子，故我們利用ink-jet plotter將其寫覆在電晶體的閘極部分後，還需利用高電壓極化法 (10kV) 使其電偶極子有規則性的排列。然後我們利用一個封閉之腔體，內部充入氮氣做為測試此空氣之壓力偵測器之實驗裝置。發現當我們增加腔體壓力時，PVDF內部之電偶極子之距離會隨之縮短，使得氮化鋁鎵/氮化鎵電晶體之表面電荷分佈改變。也會隨帶影響到介於氮化鋁鎵/氮化鎵材料之間的二維電子氣體電子密度。所以當我們在汲極以及源極間加入固定電壓時，則通過之電流會隨之改變。我們也利用不同之極化方向，得到不同之電流變化方向趨勢。在20 × 50 µm2之閘極大小之元件，我們可以量得到的最佳解析度為1 psig，也就是可分辨之解析度差異為51.7mmHg.
在氯離子感應器方面，我們以氯化銀/銀金屬做為閘極改質之材料。氯化銀材料是利用陽極氧化之方法製作。因為氯化銀/銀金屬處於氯離子濃度高的環境時，會吸附氯離子在其上，導致其表面電位改變。進而影響介於氮化鋁鎵/氮化鎵材料之間的二維電子氣體電子密度。所以當我們在汲極以及源極間加入固定電壓時，則通過之電流會隨之改變。在20 × 50 µm2之閘極大小之元件，我們可以量測得到的最低濃度解析度為1×〖10〗^(-8) M.
| zh_TW |
| dc.description.abstract | In this thesis, we study gas and liquid sensors based on AlGaN/GaN high electron mobility transistor.
For gas sensor, AlGaN/GaN high electron mobility transistors (HEMTs) with a polarized polyvinylidene difluoride (PVDF) film coated on the gate area exhibited significant changes in channel conductance upon exposure to different ambient pressures. The PVDF thin film was deposited on the gate region with an ink-jet plotter. Next, the PVDF film was polarized with an electrode located 2 mm above the PVDF film at a bias voltage of 10kV and 70℃. Variations in ambient pressure induced changes in the charge in the polarized PVDF, leading to a change in surface charges on the gate region of the HEMT. Changes in the gate charge were amplified through the modulation of the drain current in the HEMT. By reversing the polarity of the polarity of the polarized PVDF film, the drain current dependence on the pressure could be reversed. The limit of detection of our gas pressure device was 1 psig (51.7 mmHg) using a 20 × 50 µm2 gate sensing area.
For liquid sensor, AlGaN/GaN HEMTs with an Ag/AgCl gate exhibit significant changes in channel conductance upon exposing the gate region to various concentrations of chloride (Cl-) ion. The Ag/AgCl gate electrode, prepared by potentiostatic anodization, changes electrical potential when it encounters Cl- ions. This gate potential changes lead to a change of surface charge in the gate region of the HEMT, inducing a higher positive charge on the AlGaN surface, and increasing the piezoinduced charge density in the HEMT channel. These anions create an image positive charge on the Ag gate metal for the required neutrality, thus increasing the drain current of the HEMTs. The HEMTs source-drain current was highly dependent on Cl- ion concentration. The limit of detection of our device achieved was 1×〖10〗^(-8)M using a 20 × 50 µm2 gate sensing area.
| en_US |
| DC.subject | 感應器 | zh_TW |
| DC.subject | 氮化鋁鎵/氮化鎵電晶體 | zh_TW |
| DC.subject | AlGaN/GaN HEMT | en_US |
| DC.subject | chloride ion sensor | en_US |
| DC.subject | pressure sensor | en_US |
| DC.title | 以氮化鋁鎵/氮化鎵電晶體製作之空氣及氯離子感應器 | zh_TW |
| dc.language.iso | zh-TW | zh-TW |
| DC.title | Gas and Liquid Sensors based on AlGaN/GaN High Electron Mobility Transistor | en_US |
| DC.type | 博碩士論文 | zh_TW |
| DC.type | thesis | en_US |
| DC.publisher | National Central University | en_US |