Analysis Of Germanium Research Articles

Design, fabrication and analysis of germanium: silicon solar cell in a multi-junction concentrator system

A Ge:Si solar cell under a silicon solar cell can lead to as much as a 5.5% absolute efficiency gain for a multi-junction solar module at 30× concentration. This work demonstrated short circuit current densities that were 93% of the model prediction and open circuit voltages that were 92% of the model predictions for 88% Ge content, Ge:Si solar cells below Si at 30 suns. Silicon solar cells can absorb few photons in the wavelength range above 1150nm due to the effect of the absorption coefficient. One possible method to enhance the absorption of long wavelength photons is to apply a Ge solar cell below Si. However, this method is industrially impractical due to the high cost of Ge substrates. In this work, a low cost Ge:Si solar cell grown on silicon with strong long wavelength light sensitivity will be demonstrated. This work starts with an all epitaxial growth design, analyzes the performance limits, examines the trade-offs between solar cell performance, Ge composition and material quality and concludes with the pathways to higher efficiency. The high quality Ge:Si layers with Ge content above 85% were achieved on Si substrates using reduced pressure chemical vapor deposition (RPCVD) technology. Three high Ge content Ge:Si solar cells were designed, fabricated and analyzed. The encouraging results experimentally prove that low cost Ge:Si solar cells grown on Si can have high performance below Si. This has been achieved as a direct result of low dislocation density step graded Ge:Si buffers developed in this research. In this paper, the pathway to achieve low cost and high efficiency Ge:Si low band gap solar cells grown on silicon is described.

Analysis of germanium and germanium dioxide samples by mass-spectrometry and atomic emission spectroscopy

Three multielement methods: (1) inductively coupled plasma mass spectrometry (ICP-MS), (2) inductively coupled plasma atomic emission spectroscopy (ICP-AES), and (3) spark source mass spectrometry (SSMS) were used for the determination of additives in the samples of germanium and germanium oxide. The detection limits of direct SSMS and ICP-AES/ICP-MS were compared using the autoclave predissolution of germanium and germanium dioxide samples. It was shown that in the latter case, the detection limits could be significantly improved by the separation of germanium from analytes by distillation. In this case, the detection limits of such limiting elements like Th and U can reach the level n 10−10 wt %.

Analysis of germanium containing health beverages by nitrous oxide-acetylene flame atomic absorption spectrometry using discrete nebulization technique.

A simple and rapid method was developed for the analysis of total germanium (Ge), inorganic Ge (GeO2) and organic Ge (β-carboxyethyl germanium oxide ; CE-Ge) in Ge-containing health beverages. In order to determine total Ge, the sample was digested with HNO3. Ge in the sample was changed to inorganic Ge, and extracted with CCl4 as chloride. The amount of Ge was determined by polarized Zeeman atomic absorption spectrometry with a nitrous oxide-acetylene flame by using the discrete nebulization technique (FZAAS). On the other hand, inorganic Ge and organic Ge in the sample were separated by organic solvent extraction and determined by FZAAS without acid digestion. Recoveries of Ge from juice fortified at the level of 25-250 μg Ge/g were more than 92%. The calibration graph was linear between 0.25 and 20μg Ge. The proposed method was recommended for the determination of Ge and differentiation of inorganic Ge and organic Ge in Ge-containing health beverages.

Thermal Conductivity Analysis of Germanium at Low Temperatures

Thermal Conductivity Analysis of Germanium at Low Temperatures

Electron Energy Analysis of Germanium and Silica Layers on Silicon Substrates

An energy analyzing transmission electron microscope of the Möllenstedt type was used to measure the electron energy loss spectra given by various layer structures to a spatial resolution of 100Å. The technique is an important, method of microanalysis and has been used to identify secondary phases in alloys and impurity particles incorporated into epitaxial Si films.Layers Formed by the Epitaxial Growth of Ge on Si Substrates Following studies of the epitaxial growth of Ge on (111) Si substrates by vacuum evaporation, it was important to investigate the possible mixing of these two elements in the grown layers. These layers consisted of separate growth centres which were often triangular and oriented in the same sense, as shown in Fig. 1.

Determination of trace element diffusion in quartz and in germanium

Studies of mercury distribution in quartz and phosphorus and arsenic distribution in germanium are described. In the former, the samples and standard were irradiated 7 days at 5 x 10 neutrons/cm2sec. After dissolution and mercury precipitation the activity was measured on a multichannel RCL 256 spectrometer. Above 200 kev Sb126 interfered, but at 60 to 85 kev the interference became negligible. The germanium analysis was done with 24-hr irradiation at 1012 neutrons/cm2sec. Standard samples containing NH4H2PO4, (NH4)2 SO4, As2O3, and germanium were also irradiated. The irradiated samples were then dissolved in HNO3, passed over Dowex-I resin, and arsenic and phosphorus were diluted by HF. The arsenic was precipitated by H2S and the phosphorus as phosphomolybdate.