The article describes the impact of germanium on the course of surface phenomena in casting alloys of silver used in gold smithing. The aim of this works is to describe the assessment of resulting alloys, comparing the area of raw castings and the impact of the addition content of the alloy on the hardness of the samples. The evaluation also was subject to corrosion resistance of giving a comparison of their use in relations to traditional silver alloys.

Germanium (Ge) PiN photodetectors are fabricated and electro-optically characterised. Unintentionally and p-type doped Ge layers are grown in a reduced-pressure chemical vapour deposition tool on a 200 mm diameter, <001>-oriented, p-type silicon (Si) substrates. Thanks to two Ge growth temperatures and the use of short thermal cycling afterwards, threading dislocation densities down to 107 cm−2 are obtained. Instead of phosphorous (P) ion implantation in germanium, the authors use in situ phosphorous-doped poly-crystalline Si (poly-Si) in the n-type regions. Secondary ion mass spectrometry revealed that P was confined in poly-Si and did not diffuse in Ge layers beneath. Over a wide range of tested device geometries, production yield was dramatically increased, with almost no short circuits. At 30 °C and at −0.1 V bias, corresponding to the highest dynamic resistance, the median dark current of 10 µm diameter photodiodes is in the 5–20 nA range depending on the size of the n-type region. The dark current is limited by the Shockley-Read-Hall generation and the noise power spectral density of the current by the flicker noise contribution. A responsivity of 0.55 and 0.33 A/W at 1.31 and 1.55 µm, respectively, is demonstrated with a 1.8 µm thick absorption Ge layer and an optimized anti-reflection coating at 1.55 µm. These results pave the way for a cost-effective technology based on group-IV semiconductors.

In the dumps of metallurgical enterprises of Kazakhstan about 700 million tons of waste products are generated annually, and are polluting the atmosphere and the soil. The concentration of valuable components in waste products are no lower than in natural resources. The reserves of coal in the Ekibastuz basin are estimated to be more than a billion tons, and almost half of this is made up of ash. Every year, up to 30 million tons of ash-cinder waste is generated, which presents a serious threat to nature. Gallium and germanium concentrations in dumps are approximately 200 grams per ton, which is comparable to the content in coal before processing. The current research aims at creating a unit to obtain hydrogen-enriched water gas from Ekibastuz coal, with the production of zinc, gallium and germanium sublimates, copper-containing cast iron, slag wool and cast stone, through the joint processing of zinc-rich slag and ash-cinder wastes from thermal power plants. To achieve this, we used previous methods of extreme energy saving and a new method, the smelt layer with inversion phase. Experimental results from the “reactor inversion phase – rotary kiln” (RIPh) unit, which processed zinc-germanium contained slag, showed the potential to extract germanium from zinc sublimates, to reduce iron to the form of cupreous cast iron, and to obtain combustible gases and smelt suitable for slag-wool production. Calculations performed on the joint processing of Ekibastuz coal and zinc-rich slag using the proposed unit “reactor of inversion phase – rotary kiln – gas generator” showed it can obtain hydrogen-enriched water gas, along with the extraction of valuable components of primary raw material.