在固體表面上自主裝單一層分子有著廣泛的應用,例如:生化感應器、緩蝕劑、分子辨識等,文獻中也提到烷硫醇類在金表面很容易形成高度規則與穩定的單一層。本實驗嘗試在超高真空的環境下,藉由吸附及熱脫附反應探討戊硫醇(pentanethiol)在鍺表面上的穩定性。利用X射線光電子能譜儀(XPS),以不同加熱溫度鑑定在鍺表面上戊硫醇及庚硫醇之中間產物的化學組態變化,結果可得知,硫醇(thiol)、烷基硫(thiolate)、硫(atomic sulfur)三種硫型態之譜峰化學位移及面積變化。另外利用熱程控脫附儀(TPD),固定加熱速率加熱於吸附戊硫醇的鍺表面,質譜測得戊硫醇母峰(m/e=104)在溫度175 K左右出現明顯的脫附波峰,而質譜測得戊烷鏈子峰(m/e=70)在溫度175 K、370 K、600 K左右各出現明顯的脫附波峰。庚硫醇之熱變化分析結果類似,庚硫醇母峰(m/e=132)在溫度200 K左右出現明顯的脫附波峰,而質譜測得庚烷鏈子峰(m/e=70)在溫度200 K、345 K、610 K左右各出現明顯的脫附波峰。
Self-assembled monolayers (SAMs) on solid surfaces have wide range of potential applications in such areas as biochemical sensors, corrosion inhibition, and molecular recognition. Alkanethiols on gold have been frequently used to study the self-assembly process. This is because they can easily form highly ordered and stable monolayers. The adsoption and thermal desoption of 1-pentanethiol and 1-heptanethiol on Ag/Ge(111)-(√3×√3)R30° has been studied under the ultra-high vacuum (UHV) condition. Annealing of 1-pentanethiol and 1-heptanethiol on Ag/Ge(111)-(√3×√3)R30° surface resulted in the formation of thiol, thiolate and atomic sulfur based on the chemcial shift and quantitative analysis of XPS. Further TPD analysis with the heating rate of 3 K/sec showed the desorption peak at 175 K for 1-pentanethiol parent ion (m/e = 104) and desorption peaks at 175, 370, and 600 K for 1-pentanethiol daughter ion (m/e = 70) while the desorption peak at 200 K for 1-heptanethiol parent ion (m/e = 132) and desorption peaks at 200, 345, and 610 K for 1- heptanethiol daughter ion (m/e = 70).