Steps on CdSe (1120) and (1010) cleavage surfaces: Evidence for crack propagation in competing cleavage planes

We determined the structure and electronic properties of cleavage steps on CdSe (11 (2) over bar 0) and (10 (1) over bar 0) surfaces from atomically r esolved scanning tunneling microscopy images. Steps occur in high concentra tions and are always oriented parallel to the [0001] direction on both clea vage surfaces. The steps are electrically uncharged. Kinks are extremely ra re and electrically charged. The edges of steps on (11 (2) over bar 0) surf aces consist of {10 (1) over bar 0} facets and steps on (10 (1) over bar 0) surfaces exhibit {11 (2) over bar 0} facets. Steps occur preferentially in pairs (one up and one down) on both surfaces. The step structure is explai ned by a crack propagation in neighboring cleavage planes favored by the cr eation of uncharged steps. [S0163-1829(99)01504-0].