CdTe/CdS thin film solar cells grown in substrate configuration

The ability to grow efficient CdTe/CdS solar cells in substrate configuration would not only allow for the use of non‐transparent and flexible substrates but also enable a better control of junction formation. Yet, the problems of barrier formation at the back contact as well as the formation of a p–n junction with reduced recombination losses have to be solved. In this work, CdTe/CdS solar cells in substrate configuration were developed, and the results on different combinations of back contact materials are presented. The Cu content in the electrical back contact was found to be a crucial parameter for the optimal CdCl₂‐treatment procedure. For Cu‐free cells, two activation treatments were applied, whereas Cu‐containing cells were only treated once after the CdTe deposition. A recrystallization behavior of the CdTe layer upon its activation similar to superstrate configuration was found; however, no CdTe–CdS intermixing could be observed when the layers were treated consecutively. Remarkably high V_OC and fill factor of 768 mV and 68.6%, respectively, were achieved using a combination of MoO₃, Te, and Cu as back contact buffer layer resulting in 11.3% conversion efficiency. With a Cu‐free MoO₃/Te buffer material, a V_OC of 733 mV, a fill factor of 62.3%, and an efficiency of 10.0% were obtained. Copyright © 2012 John Wiley & Sons, Ltd.     

An investigation of the entomogenous fungus Beauveria bassiana (Bals.) Vuill. as a potential biological control agent for Oryzaephilus surinamensis (L.)

In laboratory experiments, a soil isolate of Beauveria bassiana (Bals.) Vuill. was found to be an effective pathogen of adult Oryzaephilus surinamensis (L.) under certain conditions. Experiments on the effect of temperature showed that infection could occur down to 7°C, the lowest temperature tested. Little difference in mortality was noted when beetles were exposed to wheat treated with a range of concentrations of B. bassiana conidiospores in suspension (10⁶, 10⁵ and 10⁴ spores ml^?1), but mortality was lower at 10³ spores ml^?1. Humidity level, however, was the critical factor in allowing infection to occur. Beetles became infected at 100% r.h. but not at 90% r.h.When conidiospores of B. bassiana were applied to 50 g wheat grain cultures of O. surinamensis, the fungus proved ineffective in killing adult beetles. Breeding success, however, was sharply reduced with a 91% decrease in numbers of larvae and pupae in cultures treated with spores of the fungus mixed with the grain.     

Providing incentives in providerless networks

This paper explores the extension of a model for the operation of an ad hoc mobile network to more general providerless networks, such as peer-to-peer systems. The model incorporates incentives for users to act as transit nodes on multi-hop paths and to be rewarded with their own ability to send traffic. The paper explores some of the trust questions that arise in this problem space and conjectures that the very structure of a peer organisation may have some hidden benefits for trust re-enforcement, that have not been previously explored (to our knowledge).     

Thermoelectric Coolers with Sintered Silver Interconnects

The fabrication and performance of a sintered Peltier cooler (SPC) based on bismuth telluride with sintered silver interconnects are described. Miniature SPC modules with a footprint of 20 mm² were assembled using pick-and-place pressure-assisted silver sintering at low pressure (5.5 N/mm²) and moderate temperature (250°C to 270°C). A modified flip-chip bonder combined with screen/stencil printing for paste transfer was used for the pick-and-place process, enabling high positioning accuracy, easy handling of the tiny bismuth telluride pellets, and immediate visual process control. A specific contact resistance of (1.4 ± 0.1) × 10^?5 Ω cm² was found, which is in the range of values reported for high-temperature solder interconnects of bismuth telluride pellets. The realized SPCs were evaluated from room temperature to 300°C, considerably outperforming the operating temperature range of standard commercial Peltier coolers. Temperature cycling capability was investigated from 100°C to 235°C over more than 200 h, i.e., 850 cycles, during which no degradation of module resistance or cooling performance occurred.     

热成像温差分辨率与微分光谱匹配因数的关系

由近距离低温面目标热成像系统的信号方程和噪声等效温差ＮＥＴＤ的定义，导出了ＮＥＴＤｏｃ１／Ｍ，并由此得到ＭＲＴＤｏｃ１／Ｍ，ＭＤＴＤｏｃ１／Ｍ，从而证明了热成像系统的温差分辨率；ＮＥＴＤ、ＭＲＴＤ、ＭＤＴＤ均要求微发光谱匹配因数Ｍ要大，这为选用光谱区配因数Ｍ和Ｍ作为热成像系统的综合评价参数奠定了理论基础。     

Probing Defects and Spin-Phonon Coupling in CrSBr via Resonant Raman Scattering

Understanding the stability limitations and defect formation mechanisms in 2D magnets is essential for their utilization in spintronic and memory technologies. Here, defects in mono- to multilayer CrSBr are correlated with structural, vibrational, and magnetic properties. Resonant Raman scattering is used to reveal distinct vibrational defect signatures. In pristine CrSBr, it is shown that bromine atoms mediate vibrational interlayer coupling, allowing for distinguishing between surface and bulk defect modes. Environmental exposure is shown to cause drastic degradation in monolayers, with the formation of intralayer defects. This is in contrast to multilayers that predominantly show bromine surface defects. Through deliberate ion irradiation, the formation of defect modes is tuned: these are strongly polarized and resonantly enhanced, reflecting the quasi--1D electronic character of CrSBr. Strikingly, pronounced signatures of spin-phonon coupling of the intrinsic phonon modes and the ion beam-induced defect modes are observed throughout the magnetic transition temperature. Overall, defect engineering of magnetic properties is possible, with resonant Raman spectroscopy serving as a direct fingerprint of magnetic phases and defects in CrSBr.