ADP晶体{100}面族微观形貌的非实时AFM(atomic force microscopy,AFM)成像表明,过饱和度σ=0.053时,晶面上出现二维成核生长;随σ增加至0.11,二维岛数量急剧增加,尺寸减小,分布渐趋均匀,二维成核生长逐渐增强,界面呈现出由光滑向粗糙转变的特征;各二维岛形状趋近于长条形,表现出各向异性,长轴平行于[001]晶向;二维岛上有单分子高度的台阶和台阶聚并后高度为2~3nm的大台阶;二维岛间融合时取向相同;σ=0.053时,融合后所形成的较大二维岛的生长呈现出周边快中心慢的情况,将可能导致产生晶体缺陷。
Surface topographies of { 100} faces of ammonium dihydrogen phosphate (ADP) crystals were investigated ex situ by atomic force microscopy (AFM). AFM images show that the beginning of 2D nucleation islands can be observed when supersaturation a is 0.053. With the increase of a up to 0.11, the number of 2D islands increases, the size becomes smaller and the distribution of 2D islands tends to uniform gradually. Meanwhile the enhanced growth of 2D nucleation causes the surface changing from smoothness to rough. The 2D islands are shaped to bars with obvious anisotropy and their long axis parallel to the [001] direction. There are monosteps with the height equal to one unit cell dimension and big steps with the height of 2-3nm on the 2D islands. The 2D islands amalgamate along the same direction. The big 2D islands from amalgamation grow slower in its center region than other areas whena is 0.053, which may result in the generation of the defect.