連續式二氧化碳雷射蒸鍍硒化鋅薄膜之特性研究

Abstract

篇研究主要探討於連續式二氧化碳雷射蒸鍍硒化鋅薄膜及砷化鎵基板其交界面和溫度對薄膜品質的影響，我們採用氨水、硫化銨( (NH4)2S)溶液及不同時間的氬離子轟擊去除砷化鎵基板的表面氧化層。經氨水和離子轟擊五分鐘基板處理於400℃成長的樣品，其XRC半高寬只有377 arcsec，同時在低溫(20K)冷激光光譜量測，相關雜質和缺陷發光強度相較於激子就顯得相當弱，拉曼譜線也量測到強且對稱的硒化鋅縱向光聲子(ZnSe-LO mode)，均顯示此法也可達到頗佳的薄膜品質，此外，我們並嘗試成長硫硒化鋅合金，藉由變化靶材混合比例，可線性的改變薄膜中的組成，所以我們相信控制好長晶速率，成長溫度及基板條件，便可以如此簡易、經濟和安全的方法來生長硒化鋅薄膜。

ZnSe and ZnSxSe1-x have been grown on GaAs (001) substrate by cw CO2 laser deposition. The effects of the growth temperature and the surface conditions of the substrate on the structural and optical properties of the thin films have been studied. We removed the oxide layer on substrate by different chemical solution (NH4OH, (NH4)2S) and ion beam bombardment time. After NH4OH-treated and ion bombardment 5 minutes, the XRC FWHM value of ZnSe is 377 arcsec for our 400℃sample. The clear exciton and weak DAP, S band, Y-line emission in 20K PL spectra reflect low density of defects and impurity. Besides, strong and symmetric ZnSe-LO phonon mode is the evidence of good film quality. The composition x in the films of alloy ZnSxSe1-x can be linearly controlled by the ZnS/ZnSe ratio in target. By properly choosing the growth rate, growth temperature and substrate surface condition, we have demonstrated a feasible and less expensive method to deposit ZnSe film.