Mercury chalcogenides

Studies of the electrodeposition of mercury chalcogenides are scarce, primarily because of the difference in electrochemical potentials needed to deposit mercury and the chalcogens. Mercury is a noble metal the standard redox potential for the 

The properties of anodic layers of HgS formed on mercury in sulfide solutions have been investigated in comparison with anodic sulfide layers of cadmium and bismuth. Also, the electrochemistry of mercury electrodes in aqueous selenite solutions has been studied (see Sect. 3.2.1). The problem with the presence of several cathodic stripping peaks for HgSe in acidic Se(IV) solutions has been addressed using various voltammetric techniques at a hanging-mercury-drop electrode [119]. 

The chemical bath deposition of polycrystalline, zinc blende HgSe thin films on TO glass from aqueous alkaline medium has been reported [120]. Examples of electrodeposited ternary mercury compounds will be discussed in the next section. 

Thin films of ternary cadmium sulfoselenide CdS Sei-x have been electrodeposited from a non-aqueous organic bath by Baranski et al. [67], as well as by Loutfy and Ng [121], who employed similar principles (deposition from ethylene glycol solution 

Cathodic electrodeposition of microcrystalline cadmium-zinc selenide (Cdi i Zn i Se CZS) films has been reported from selenite and selenosulfate baths [125, 126]. When applied for CZS, the typical electrocrystallization process from acidic solutions involves the underpotential reduction of at least one of the metal ion species (the less noble zinc). However, the direct formation of the alloy in this manner is problematic, basically due to a large difference between the redox potentials of and Cd couples [127]. In solutions containing both zinc and cadmium ions, Cd will deposit preferentially because of its more positive potential, thus leading to free CdSe phase. This is true even if the cations are complexed since the stability constants of cadmium and zinc with various complexants are similar. Notwithstanding, films electrodeposited from typical solutions have been used to study the molar fraction dependence of the CZS band gap energy in the light of photoelectrochemical measurements, along with considerations within the virtual crystal approximation [128]. 

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The most important mercury chalcogenide halides are of the type HgaYjXj (Y = S, Se, Te X = Cl, Br, I). The corresponding sulfide halides have been known for over 150 years (326). Quite a lot of work has been performed concerning the preparation, structures, electronic and optical properties, and phototropic behavior of these compounds. Mercury chalcogenide halides of other compositions have been mentioned in the literature (141). As most of these compounds are not well established, they will not be treated in detail, with the exception of the latest contributions (see Table V). 

Table VI summarizes the structural data on mercury chalcogenide halides.

The phototropic behavior of the mercury chalcogenide halides has received particular attention. This interest was stimulated by the hope that these materials might allow the preparation of photolayers capable of repeated use for the production of images. 

Lombos BA, Lee EYM, Kipling AL, Krawczyniuk RW (1975) Mercury Chalcogenides, Zero gap semiconductors. J Phys Chem Solids 36 1193-1198... 

Fast-scan electrochemical techniques, 46 163 F-Centers, and mercury chalcogenide halides, 23 356-357... 

There are only several reports on the deposition of the mercury chalcogenides (some ternaries containing Hg have also been described). 

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