Laser interf erometry of electroless deposition of copper selenide

Comparison characterization of copper selenide thin layers prepared on polyamide 6 films by sorption-diffusion method

Some earlier synthesized copper selenide (Cux Se) layers formed on the surface of polyamide 6 by sorption-diffusion method using potassium selenotrithionate (K2SeS2O6) as precursor of selenium were characterized by the XRD, XPS and SEM methods. According to the results of the SEM studies, the most uniform Cux Se layers form at the 2.5 h polyamide seleniumized duration at the temperature of 60°C. The thickness of layers, which dependeds on the duration of seleniumization, changed in the range of 0.8–3.2 µm. The XRD patterns of not previously studied Cux Se layers showed their phase composition of six copper selenides: Cu2Se, two phases of CuSe2, Cu3Se2, berzellianite, Cu2-x Se, and bellidoite Cu2Se. Analysis of the XRD and XPS data shows that the macrostructure and composition of the CuxSe layers depend on the conditions of formation of these layers.

Electrosynthesis of Cu−Se Films on Copper Electrodes in Alkaline Media: A Voltammetric, Electrochemical Quartz Crystal Microbalance and I/t Transient Study

The electroformation of Cu-Se phases, obtained by selenizing a thin film of copper deposited on the quartz/gold electrode system, was studied with an electrochemical quartz crystal microbalance (EQCM) and by cyclic voltammetry (CV) in an alkaline solution (0.05 M Na(2)B(4)O(7)) containing selenide ion. Potentiodynamic parameters showed that the formation of the initial Cu-Se phases (Cu(2-x)Se/Cu(3)Se(2)) is ruled by an irreversible diffusion controlled mechanism, where a first electron transfer is the rate-determining step. A CV study was also performed with a bulk copper electrode in 1 M NaOH solution containing selenide ion. The deconvolution of the anodic and cathodic I/E profiles corresponding to the electroformation and electroreduction of the Cu-Se film formed allowed us to establish that, depending on the anodic potential limit of the potentiodynamic scan, the Cu-Se phases formed were either a mixture of Cu(2)(-x)Se/Cu(3)Se(2) or Cu(2-x)Se/Cu(3)Se(2)/CuSe. An EQCM study showed that, during the initial stage of Cu-Se phase electroformation, water molecules were released from the electrode. In advanced stages of the process, when the electrode was completely covered by Cu-Se compounds, selenide anions were adsorbed on the formed phase. When the anodic potential limit was extended to -0.2 V, copper oxide compounds were formed. The analysis of the cathodic charge related to Cu-Se phase electroreduction and Energy Dispersive X-ray Spectroscopy (EDXS) analysis confirmed that when the anodic limit was -0.8 V, a mixture of different Cu-Se phases was formed. A I/t transient study performed with a bulk copper electrode in alkaline solution containing selenide established that the nucleation and growth mechanism (NGM) of the Cu-Se phases takes place through an initial bidimensional-instantaneous nucleation (IN2D), followed by four bidimensional-progressive nucleations (PN2D). These results and atomic force microscopy (AFM) experiences supported that the growth of the Cu-Se films occurs through a layer-by-layer mechanism.

Pyridineselenolate Complexes of Copper and Indium: Precursors to CuSe(x)() and In(2)Se(3)

The pyridineselenolate (2-Se-NC(5)H(4), (SePy)) and the 3-(trimethylsilyl)pyridineselenolate (3-Me(3)Si-2-Se-NC(5)H(4) (SePy)) ligands form air-stable homoleptic coordination compounds of Cu(I) { [Cu(SePy)](4) (1) and [Cu(SePy)](4) (2)} and In(III) {In(SePy)(3) (3) and In(SePy)(3) (4)}. Mass spectroscopic characterization of the Cu(I) compounds indicated a tetrametallic core, and this was confirmed with a single-crystal X-ray structural characterization of crystalline 1 and 2, which both contain a tetrametallic cluster of Cu(I) ions bound to two doubly bridging Se atoms and a pyridine nitrogen. The Cu coordination sphere is completed with two strong Cu-Cu bonds and one weaker Cu-Cu interaction. The indium compounds 3 and 4 are each distorted fac-octahedral molecules with chelating SePy ligands. These compounds are useful low-temperature precursors to the binary selenides. Both 3 and 4 sublime intact; 3 thermally decomposes to give In(2)Se(3). The Cu clusters do not sublime intact but still decompose to give metal selenide phases: 2 decomposes to give pure alpha-CuSe at low temperatures and increasing amounts of Cu(2)(-)(x)()Se at elevated temperatures, while 3 decomposes to give a mixture of CuSe phases at all temperatures. Crystal data (Mo Kalpha: 1, 153(5) K; 2-4, 293(2) K) are as follows: 1, monoclinic space group C2/c, a = 20.643(5) Å, b = 16.967(2) Å, c = 16.025(2) Å, beta = 114.16(2) degrees, Z = 8; 2, tetragonal space group I4(1)/a, a = 14.756(3) Å, c = 19.925(3) Å, Z = 4; 3, trigonal space group P&thremacr;c1, a = 13.352(2) Å, c = 13.526(2) Å, Z = 4; 4, monoclinic space group P2(1)/c, a = 9.793(1) Å, b = 20.828(6) Å, c = 16.505(1) Å, beta = 96.69(1) degrees, Z = 4.