摘要
本文采用探测室可转动的分子束实验装置,研究了氯分子束与GaAS(100)表面热反应和紫外激光诱导反应的动力学.结果表明.热反应的主要产物为GaCl_3,其角分布可用cos^(2.3)θ函数拟合.对于紫外(355nm)激光诱导反应,由角分辨的飞行时间(TOF)法测得主要产物为GaCl等,它们的通量角分布须用双余弦加和公式(c_1cosθ+c_2cos^nθ)拟合,表示产物粒子在表面法线方向明显聚集,而且由TOF谱求得粒子的动能在表面法线方向最大.这种明显的聚集现象可以由激光诱导的粒子在表面附近发生碰撞效应来解释.
A rotatable mass spectrometer coupled with a Cl2 supersonic molecular beam scattering technique is used to examine the fundamental processes involved in thermal reaction and 855 nm laser-induced chemical etching of GaAs(100) surface with a Cl2 molecular beam. The results of the thermal reaction of QaAs/Cl2 system show that GaCl3 is the main product and its angular distribution can be fit with cos2.3 θ function. For the UV laser-induced reaction, the main reaction products are GaCl and Ga. The time-of-flight (TOF) spectra of these reaction products are measured as a function of the scattering angle, laser fluence and incident anglo of the chlorine beam. The measured flux angular distribution of desorbing GaCl can be fit satisfactory with a function of (c1cos θ + c2 cos' θ). It implies that the desorbing products are strongly collected at the direction of the surface normal, the kinetic energies of products are peaked around this direction. These phenomenon can be interpreted in terms of post-desorption collisions.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
1994年第2期105-110,共6页
Acta Chimica Sinica
基金
高等学校博士学科点专项科研基金
