Effect Of Annealing On The Behavior Of Oxygen Dissolved In Germanium And Optical Properties Of Single Crystals

The annealing effect in the temperature range from 350 to 450 °С on the behavior of interstitial oxygen Оi dissolved in germanium and on optical properties of single crystals has been investigated by Fourier transformed infrared spectrometry. It was found that oxygen band maximum of 843 cm–1 shifted toward the 856 cm−1 with oxygen concentration increasing after annealing at the oxygen partial pressure ranged from 1 to 103 Pа. The annealing at lower  values led to the decrease of 843 cm–1 band intensity due to the formation of thermal donors (TD) on the basis of dissolved oxygen atoms Оi. It was established that TD formation and the decrease of unbound oxygen concentration affected optical properties of the crystals

Amorphous Silica Containers for Germanium Ultrapurification by Zone Refining

We have studied the wetting behavior of molten germanium on silica ceramics and amorphous silica coatings in vacuum at a pressure of 1 Pa and a temperature of 1273 K. The results demonstrate that the wetting of rough surfaces of ceramic samples and coatings by liquid Ge is significantly poorer than that of the smooth surface of quartz glass. The contact angle of polished glass is ~100°, and that of the ceramics and coatings increases from 112° to 137° as the total impurity content of the material decreases from 0.120 to 1 × 10–3 wt %. Using experimental contact angle data, we calculated the work of adhesion of molten Ge to the materials studied. Its value for the surface of the ceramics and coatings decreases from 0.45 to 0.20 J/m2 with decreasing impurity content, whereas the work of adhesion to a smooth glass surface is 0.55 J/m2. We have fabricated fused silica test containers coated with high-purity amorphous silica. Using horizontal zone refining, we obtained germanium samples with a carrier concentration difference on the order of 1011 cm–3

Amorphous Silica Containers for Germanium Ultrapurification by Zone Refining

We have studied the wetting behavior of molten germanium on silica ceramics and amorphous silica coatings in vacuum at a pressure of 1 Pa and a temperature of 1273 K. The results demonstrate that the wetting of rough surfaces of ceramic samples and coatings by liquid Ge is significantly poorer than that of the smooth surface of quartz glass. The contact angle of polished glass is ~100°, and that of the ceramics and coatings increases from 112° to 137° as the total impurity content of the material decreases from 0.120 to 1 × 10–3 wt %. Using experimental contact angle data, we calculated the work of adhesion of molten Ge to the materials studied. Its value for the surface of the ceramics and coatings decreases from 0.45 to 0.20 J/m2 with decreasing impurity content, whereas the work of adhesion to a smooth glass surface is 0.55 J/m2. We have fabricated fused silica test containers coated with high-purity amorphous silica. Using horizontal zone refining, we obtained germanium samples with a carrier concentration difference on the order of 1011 cm–3