High Intensity Low Temperature (HILT) performance of space concentrator GaInP/GaInAs/Ge MJ SCs

In the work, the results of an investigation of GaInP/GaInAs/Ge MJ SCs intended for converting concentrated solar radiation, when operating at low temperatures (down to -190 degrees C) are presented. A kink of the cell I-V characteristic has been observed in the region close to V-oc starting from -20 degrees C at operation under concentrated sunlight. The causes for its occurrence have been analyzed and the reasons for formation of a built-in potential barrier for majority charge carriers at the n-GaInP/n-Ge isotype hetero-interface are discussed. The effect of charge carrier transport in n-GaInP/n-p Ge heterostructures on MJ SC output characteristics at low temperatures has been studied including EL technique

Characterization of the manufacturing processes to grow triple-junction solar cells

A number of important but little-investigated problems connected with III-V/Ge heterostructure in the GaInP/GaInAs/Ge multijunction solar cells grown by MOVPE are considered in the paper. The opportunity for successfully applying the combination of reflectance and reflectance anisotropy spectroscopy in situ methods for investigating III-V structure growth on a Ge substrate has been demonstrated. Photovoltaic properties of the III-V/Ge narrow-band subcell of the triple-junction solar cells have been investigated. It has been shown that there are excess currents in the Ge photovoltaic p-n junctions, and they have the tunneling or thermotunneling character. The values of the diode parameters for these current flow mechanisms have been determined. The potential barrier at the III-V/Ge interface was determined and the origin of this barrier formation during MOVPE heterogrowth was suggested

Сравнительная характеристика типичной и атипичной (микоплазменной) пневмонии у детей

Aim: To compare the features of clinical-anamnestic and laboratory-instrumental data and treatment of children with typical and atypical (Mycoplasma) forms of pneumonia.Materials and methods. A comparative analysis was carried out of 1 70 case histories of children in hospital with a verified diagnosis of pneumonia in 2020. The basis for the diagnosis of Mycoplasma pneumonia was a positive PCR result of a smear of the posterior pharyngeal wall. The resulting data was constructed using Microsoft Excel 2007.Results. Mycoplasma pneumonia is specific for older schoolchildren; characterized by: prolonged course (73.5%), long-term preservation of an unproductive cough (75.7%), mild intoxication (68.6%) and catarrhal syndromes (54.3%), gradual onset (76.6%), severe lymphocytosis up to 55%, segmental or polysegmental damage to the lung tissue (92.7%).Цель: сравнить особенности клинико-анамнестических и лабораторно-инструментальных данных у детей с типичной и атипичной (микоплазменной) пневмонией.Материалы и методы. Был проведен сравнительный анализ 170 историй болезни детей, находящихся на стационарном лечении с верифицированным диагнозом пневмония в ДИБО БУЗ УР «ГКБ №7 МЗ УР» в 2020 г. Основанием для постановки диагноза микоплазменной пневмонии являлся положительный результат ПЦР мазка задней стенки глотки. Полученные данные были сконструированы с помощью Microsoft Excel 2007.Результаты. Микоплазменная пневмония специфична для детей старшего школьного возраста и характеризуется затяжным течением (73,5%), длительным сохранением малопродуктивного кашля (75,7%), слабо выраженными интоксикационным (68,6%) и катаральным синдромами (54,3%), постепенным началом (76,6%), выраженным лимфоцитозом до 55%, сегментарным или полисегментарным поражением легочной ткани (92,7%)

Admittance spectroscopy of InGaAsN based solar cells

International audienceSingle-junction InGaNAs solar cells were grown by MBE with active layers based on a GaAsN/InAs superlattice. Dependence of defect formation on thickness of InGaNAs was explored in the study. Thickness increase from 900 nm to 1200 nm leads to defect formation with two activation energies of 0.20 eV and 0.50 eV but the value of quantum efficiency stays almost the same. Further thickness increase up to 1600 nm leads to the increase of defect concentration in the InGaNAs active layer. These defects are non-radiative recombination centres because a significant decrease of solar cell quantum efficiency was observed. The existence of a critical thickness for defect-free growth of InGaNAs based on GaAsN/InAs superlattice is proposed. 1. Introduction In 2015 multi-junction solar cells (MJ SC) based on III-V compounds with a record efficiency of 46% were fabricated [1]. Triple-junction SC based on the GaInP (1.85 eV) / GaAs (1.42 eV) / Ge (0.7 eV) system are used in industry for space applications where the key factors are efficiency and resistance to radiation. But its concentrator efficiency has almost reached the theoretical limit (46%) and now its value is more than 40% [2]. Fortunately, according to theoretical estimations an additional subcell with energy bandgap of 1 eV could increase the SC efficiency up to 52% [3]. However, such subcell should be lattice-matched to Ge and GaAs wafers. Ga1-xInxNyAs1-y with a small content of nitrogen is one of the most promising alloys to reach this goal. Such III-V-N alloys (GaPNAs, InGaNAs etc.) with nitrogen content less than 5% are called dilute nitrides. It has been shown that the small addition of nitrogen leads to large bowing parameters for the bandgap in quaternary Ga1-xInxNyAs1-y alloys: already few percent of nitrogen reduces the bandgap by hundreds of meV [4] and a value of 1 eV can be achieved. Furthermore, these layers can be epitaxially grown on Ge and GaAs wafers when y=0.35x. Various groups [3, 5-8] studied InGaNAs layers grown by epitaxy, but the quality is not sufficient for fabrication of high-efficiency solar cells. The low lifetime of charge carriers is the most crucial issue in dilute nitrides. The main reason is the high concentration of non-radiative recombination centers in active layers. In MOCVD (metal-organic chemical-vapor deposition) it comes from the background doping of carbon and hydrogen during the process. On the other hand, MBE (molecular-beam epitaxy) allows one to avoid these problems and enables to control the flow of nitrogen more precisely. However, a lower proces