Wafer preparation cleaning procedures

Samples were prepared from dilute toluene solutions by spincoating thin films onto the wafers. The polymer adsorbed onto the oxide surface of silicon wafers which were cleaned in a water-saturated UV-ozone atmosphere. By this cleaning procedure, we created a surface with a high density of hydroxyl groups. The initial film thickness has been determined by eUipsometry. Crystallization and subsequent thermal treatment (annealing) were performed directly under an optical microscope in an inert atmosphere (nitrogen flow). 

Wafers were prepared, sulfided and evacuated (2 h at 673 K) as described above. The temperature was then set at 423 K and 80 kPa of purified deuterium (Air Liquide, N28) was admitted into the cell. The purification procedure consisted of passing the gas through a moisture filter (Chrompack Gas Clean 7971), an oxygen filter (Chrompack Gas Clean 7970) and a liquid nitrogen trap. 

Procedure. The rock wafers were gently cleaned three successive times with methanol in an ultrasonic bath, dried and placed in the inert atmosphere box. Two wafers of each rock type were inserted horizontally in stainless steel holders and placed in linear polyethylene containers holding 150 ml of the appropriate prepared water. The wafers were allowed to equilibrate with the water for three days and then 5 X of tracer solution was added. The resultant solutions contained V/ 5x10 M of each element. The pH of each solution was measured before and after the addition of the tracer and did not change sign-... 

Sample Preparation. Gold slides were prepared by evaporation of ca. 2000 A of gold (99.99%, Balzers, Liechtenstein) with a deposition rate of ca. 15 A/s onto silicon wafers, which had previously been coated to a depth of ca. 60 A with chromium (99.99%, Balzers, Liechtenstein) as an adhesion promoter. This procedure was carried out in a Balzers MED 010 coater, operating at a pressure of ca. 10 mbar during evaporation. After the evaporation process was finished, the chamber was flushed with argon. Glassware was cleaned with methylene chloride or methanol. The slides were kept under argon. 

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