涂覆法观测kh2po4晶体Z切片薄表面层形成和生长特性

Experimental Investigation on the Formation and Growth Characteristics of Thin Surface Layer at Z-cut KH_2PO_4 Plate by Coating Method

提出一种实验研究薄表面层形成和生长的涂覆法。利用该方法,以KH_2PO_4(KDP)晶体Z切片为载体,探究晶体的某些部位,比如(001)面、棱边、柱面在薄表面层形成以及生长过程中所起的作用。结果表明,当Z切片的(001)面上的棱边被覆盖,会首先以小晶锥的形式在(001)面形成新棱边,然后自新棱边沿(101)面切线方向出现薄表面层生长;当整个(001)面被覆盖,柱面生长一定时间并形成新棱边,之后也会出现薄表面层生长;当(001)面被涂覆分割,各分割部分能在各自的新棱边形成后以薄表面层方式形成独立的锥体,而在锥体间的棱边恢复后,独立锥体相应锥面能实现连接。可见,棱边是薄表面层形成的先决条件。对各种涂覆处理的Z切片通过光学显微镜实时观测,发现棱边在薄表面层形成中起关键作用,而柱面能提供台阶,在薄表面层生长中起重要作用;同时,得到了不同涂覆处理方式下薄表面层切向生长速度和动力学系数。

A coating method applied to experimentally investigation of the formation and growth of thin surface layer was proposed.By this method,the effects of(001)face,edge and prismatic surface on the formation of KH2PO4(KDP)Z cut plate thin surface layers were analyzed.It showed that the small crystals on(001)face grew,creating new(001)edges and then the growth of thin surface layers was emerged along the tangential direction of the new edge when(001)edges were coated.When the whole(001)face were coated,the growth of(100)faces would form the new(001)edges from which the growth of thin surface layers started.When the(001)surface was divided into several parts by coating material,an independent pyramid could form on each segment as the thin surface layer from the new edge.After the edge between the independent pyramid was restored,the corresponding face of the independent pyramid could be connected.Therefore,it could be inferred that the existence of edge was a prerequisite for the formation of thin surface layers.In situ observation experiment on the growth of coated Z cut plate by the aid of optical microscopy was also conducted.It was found that edge played a key role in the formation of thin surface layers,moreover,prismatic surface played an important role by providing growth step for the growth of thin surface layers.Meanwhile,the relationship between the corresponding thin surface tangential growth speed and kinetic coefficient was obtained.