AFM Investigation on Step Bunching on (100) Face of KDP Crystal

The dependence of growth rate of(100) face of KDP crystal on supersaturation was measured using the laser polarization interference technique.Morphologies of both elementary steps and macrosteps were investigated by using AFM technique at a serial of supersaturation.Furthermore,the bunching process as well as the influence of supersaturation on bunching process was analyzed according to the AFM results.The results show that at the su-persaturation of 1.8%,elementary steps are in priority on(100) face,whose height is 0.366 nm,equivalent to half of the unit cell.When the supersaturation is increased,elementary steps begin bunching together.At the initial bunch-ing stage,the step height and step width are increased.With a rise of supersaturation,more elementary steps par-ticipate in the bunching process,and the velocity of the macrosteps increasease as well.At the same time,the slops of the macrosteps reach stable ultimately.