Photoetching effects in mercuric iodide

Photoetching effects during the chemical dissolution of mercuric iodide in an iodide solution may produce noticeable surface roughening while the mean etch rate, to a first approximation, is not modified. As this phenomenon is directly related to the formation during etching of a surface chemical complex that absorbs light, the presence or not of light is an important factor in the case of KI and NH4 I etching. In contrast, the surface roughness produced after HI etching is essentially light insensitive. q2000 Elsevier Science B.V. All rights reserved.