One of the primary goals of the space exploration community is to unambiguously detect past or present life outside of Earth.As such,a number of so-called life detection technologies,instruments,and approaches have be...One of the primary goals of the space exploration community is to unambiguously detect past or present life outside of Earth.As such,a number of so-called life detection technologies,instruments,and approaches have been applied as part of past,current,and future space missions.As astrobiology is a truly interdisciplinary field within the realm of space exploration with major contributions from physical and biological sciences(among others),recently there has been development of a number of relevant techniques from scientific fields that have yet to be fully applied to extraterrestrial life detection.As a culmination of the 2021 Blue Marble Space Institute of Science(BMSIS)Young Scientist Program(YSP),we present a number of techniques drawn from various fields(including,but not limited to,chemistry,materials science,biology,nanotechnology,medical science,astrophysics,and more)that either have been or have the potential to be applied to life detection research.These techniques broadly fall under three categories:instrumentation for in situ measurements of biosignatures within the solar system,calculations or observational techniques for remote measurements of exoplanet biosignatures,and technosignatures.We hope that this primer serves to inspire the field to consider applying more potential technologies from adjacent fields into any of these three categories of life detection.展开更多
Physical and electronic asymmetry plays a crucial role in rectifiers and other devices with a directionally variant current-voltage(I-V)ratio.Several strategies for practically creating asymmetry in nanoscale componen...Physical and electronic asymmetry plays a crucial role in rectifiers and other devices with a directionally variant current-voltage(I-V)ratio.Several strategies for practically creating asymmetry in nanoscale components have been demonstrated,but complex fabrication procedures,high cost,and incomplete mechanistic understanding have significantly limited large-scale applications of these components.In this work,we present density functional theory calculations which demonstrate asymmetric electronic properties in a metal-semiconductor-metal(MSM)interface composed of stacked van der Waals(vdW)heterostructures.Janus MoSSe has an intrinsic dipole due to its asymmetric structure and,consequently,can act as either an n-type or p-type diode depending on the face at the interior of the stacked structure(SeMoS-SMoS vs.SMoSe-SMoS).In each configuration,vdW forces dominate the interfacial interactions,and thus,Fermi level pinning is largely suppressed.Our transport calculations show that not only does the intrinsic dipole cause asymmetric I-V characteristics in the MSM structure but also that different transmission mechanisms are involved across the S-S(direct tunneling)and S-Se interface(thermionic excitation).This work illustrates a simple and practical method to introduce asymmetric Schottky barriers into an MSM structure and provides a conceptual framework which can be extended to other 2D Janus semiconductors.展开更多
基金the primary outcome of a summer research intern-ship with the Blue Marble Space Institute of Science(BMSIS)2021 Young Scientist Program(YSP)G.E.L.is partially funded through the NASA Shared Services Center grant“An Integrated Approach Towards Understanding Planetary Environments For The Origin And Detectability Of Life”(grant number 80NSSC18M0064)。
文摘One of the primary goals of the space exploration community is to unambiguously detect past or present life outside of Earth.As such,a number of so-called life detection technologies,instruments,and approaches have been applied as part of past,current,and future space missions.As astrobiology is a truly interdisciplinary field within the realm of space exploration with major contributions from physical and biological sciences(among others),recently there has been development of a number of relevant techniques from scientific fields that have yet to be fully applied to extraterrestrial life detection.As a culmination of the 2021 Blue Marble Space Institute of Science(BMSIS)Young Scientist Program(YSP),we present a number of techniques drawn from various fields(including,but not limited to,chemistry,materials science,biology,nanotechnology,medical science,astrophysics,and more)that either have been or have the potential to be applied to life detection research.These techniques broadly fall under three categories:instrumentation for in situ measurements of biosignatures within the solar system,calculations or observational techniques for remote measurements of exoplanet biosignatures,and technosignatures.We hope that this primer serves to inspire the field to consider applying more potential technologies from adjacent fields into any of these three categories of life detection.
基金supports from the NSF of China(51722102,21773120,51602155)the NSF of Jiangsu Province(BK20180448)+1 种基金the Fundamental Research Funds for the Central Universities(30920041116,30920021159,30919011405)Jiangsu Key Laboratory of Advanced Micro&Nano Materials and Technology.
文摘Physical and electronic asymmetry plays a crucial role in rectifiers and other devices with a directionally variant current-voltage(I-V)ratio.Several strategies for practically creating asymmetry in nanoscale components have been demonstrated,but complex fabrication procedures,high cost,and incomplete mechanistic understanding have significantly limited large-scale applications of these components.In this work,we present density functional theory calculations which demonstrate asymmetric electronic properties in a metal-semiconductor-metal(MSM)interface composed of stacked van der Waals(vdW)heterostructures.Janus MoSSe has an intrinsic dipole due to its asymmetric structure and,consequently,can act as either an n-type or p-type diode depending on the face at the interior of the stacked structure(SeMoS-SMoS vs.SMoSe-SMoS).In each configuration,vdW forces dominate the interfacial interactions,and thus,Fermi level pinning is largely suppressed.Our transport calculations show that not only does the intrinsic dipole cause asymmetric I-V characteristics in the MSM structure but also that different transmission mechanisms are involved across the S-S(direct tunneling)and S-Se interface(thermionic excitation).This work illustrates a simple and practical method to introduce asymmetric Schottky barriers into an MSM structure and provides a conceptual framework which can be extended to other 2D Janus semiconductors.
