Etching behavior single crystal

While the microscopic etch mechanism of ZnO single crystals in alkaline and acid solutions is well understood [109,117], a detailed understanding of the etching behavior of compact polycrystalline films is still not available. In the following we will discuss the relation between etching behavior of... 

As a general caveat, note that an interpretation of etch results in terms of surface termination is difficult, as the microscopic structure of ZnO single crystal or ZnO Al film surfaces is unknown. Effects like surface reconstruction or presence of adsorbates may constitute the main factor determining the etching behavior, thus masking all other effects [135], A direct microscopic... 

The above cited factors influencing the hole injection kinetics have important consequences on the dark open-circuit etching behavior of GaP single crystals in alkaline Fe(CN) solutions. At the (lll)-face, the open-circuit etching rate is always found to be controlled by the rate of the charge transfer reaction (so-called kinetic control). At the (lll)-face, on the other hand, the etching rate is always found to be limited by ion diffusion towards the semiconductor surface, either of Fe(CN) (for Fe(CN) concentrations lower than 0.3 mol -1 or of OH (for Fe(CN) concentrations higher than 0.3 mol 1 ). This difference between the two polar... 

As stated in Sec. 3.1, valuable information on the mechanism of chemical etching processes can similarly be obtained by studying the electrochemical behavior of the interface. In the particular case of GaP, the conclusion that open-circuit etching of GaP single crystals in acidic Br2 solutions proceeds via a chemical mechanism arises from two experimental observations. Firstly, current-potential measurements at p-GaP show that Br2 cannot inject holes into the valence band of GaP, so that elec-... 

In order to discuss the correlation between etching kinetics and etching morphology, let us first reconsider the current-potential characteristics of III-V semiconductors, as depicted in Fig. 1. For the sake of clarity, the behavior in alkaline solutions (Fig. 1 (b)) is treated first. As announced, the discussion is mainly based on experimental results obtained from GaP single crystals. 

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