本論文的主題是以低能量電子繞射術、歐傑電子能譜術以及紫外光電子能譜術，研究鈷超薄膜在鉑(111)表面上的成長行為和合金形成；其內容包含起初的成長、交互擴散的動態研究、退火後的表面組成和結構相圖。在室溫及低溫下鈷超薄膜的成長呈現非同調性的磊晶，而在五個原子層的鍍量以上，低溫狀態下成長出的超薄膜其表面結構較粗糙；由交互擴散的動態研究可得到擴散活化能為0.9電子伏特，指數前擴散參數為6.6x10-11cm2/s；一個原子層的鈷超薄膜經過退火處理後，第一原子層和第二原子層各佔百分之五十的鈷原子；在此系統上，第一次發現兩個原子層的鈷超薄膜經過退火處理後，出現旋轉4.9度的區域；由低能量電子繞射術決定出的結構相圖展現出此系統多樣化的結構，有假性(1x1)、非同調性的磊晶、額外的p(2x2)、旋轉的非同調性的磊晶以及合金化的(1x1)結構。此外也研究銀超薄膜在鉑(111)表面上的成長行為和合金形成作為對比；銀在鉑(111)表面上的成長是依SK模式；一個原子層以內的銀超薄膜經過退火處理後，由於二維的銀鉑表面合金形成，會造成表面結構有異常的變化；一個原子層以上的銀超薄膜則不形成表面合金。
Low-energy electron diffraction (LEED), Auger electron spectroscopy (AES) and ultraviolet photoelectron spectroscopy (UPS) were used to study the growth behavior and the alloy formation of the cobalt ultrathin film on a Pt(111) surface. Initial growth, kinetics of inter-diffusion, surface composition after annealing and structural phase diagram have been represented in this thesis. Cobalt ultrathin film shows an incoherent epitaxy for depositing on Pt(111) at room and low temperatures. A rougher surface structure is observed for high coverages at low temperature. From the kinetic study of the inter-diffusion, activation energy and pre-exponential diffusion coefficient are obtained to be 0.90 eV and 6.6x10-11 cm2/s respectively. After annealing the one-monolayer Co ultrathin film on a Pt(111) surface at 600 K, both the topmost and the second layers contain 50 % of Co atoms. Rotated Co domains of rotation angle 4.9° with respect to the aligned substrate are observed for 2 monolayers of Co/Pt(111) af-ter annealing treatment. The structural phase diagram is obtained from LEED observation. Some structural phases of this system were observed: pseudo (1x1), incoherent epitaxy, extra p(2x2), rotational incoherent epitaxy, and alloying (1x1) structures. The changes in valence band structures during initial and phase transitions are studied by UPS. The Ag/Pt(111) ultrathin films are studied to compare with the Co/Pt(111) system. The growth of Ag/Pt(111) belongs to the Stranski-Krastanov (SK) mode. The surface structure has abnormal change between 550 K and 650 K in a submonolayer range because a disordered 2D Ag-Pt alloy is formed on the top layer.