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Ferroelectric memories based on hafnium oxide are an attractive alternative to conventional memory technologies due to their scalability and energy efficiency. However, there are still many open questions regarding the optimal material stack and processing conditions for reliable device performance. Here, we report on the impact of the sputtering process conditions of the commonly used TiN top electrode on the ferroelectric properties of Hf1-xZrxO2. By manipulating the deposition pressure and chemistry, we control the preferential orientation of the TiN grains between (111) and (002). We observe that (111) textured TiN is superior to (002) texturing for achieving high remanent polarization (Pr). Furthermore, we find that additional nitrogen supply during TiN deposition leads to >5× greater endurance, possibly by limiting the scavenging of oxygen from the Hf1-xZrxO2 film. These results help explain the large Pr variation reported in the literature for Hf1-xZrxO2/TiN and highlights the necessity of tuning the top electrode of the ferroelectric stack for successful device implementation.

There is currently an emerging drive towards computational materials design and fabrication of predicted novel materials. One of the keys to developing appropriate fabrication methods is determination of the composition and phase. Here we explore the FeGe system and establish reference Raman signatures for the distinction between FeGe hexagonal and cubic structures, as well as FeGe2 and Fe2Ge3 phases. The experimental results are substantiated by first principles lattice dynamics calculations as well as by complementary structural characterization such as transmission electron microscopy and X-ray diffraction, along with magnetic measurements.

InSb has the smallest bandgap and highest electron mobility among III‐V semiconductors and is widely used for photodetectors and high‐frequency electronic applications. Integration of InSb directly on Si would drastically reduce the fabrication cost and enable new applications, however, it is very challenging due to its 19% lattice mismatch with Si. Herein, the integration of single‐crystalline InSb microstructures on insulator‐covered Si through rapid melt growth (RMG) is reported and specifically provides details on the fabrication process. The importance of achieving high‐quality conformal capping layers at low thermal budget to contain the InSb melt is assessed when the sample is annealed. The importance of ensuring a pristine Si seed area to achieve single‐crystalline InSb is illustrated and demonstrated here for the first time.

Aspirations bring different versions of the future into the present. This introductory essay asks what we can learn by attending to the myriad ways in which rural subjects and collectivities articulate and institutionalise aspirations. We argue that aspirations are conditioned by constellations of power, which shape what can be done and what can be imagined. These visions of alternative futures can be either affirmative or transformative, but will always entail negotiations over the meaning of self and community. This conceptualisation cautions against policymaking based on individualised aspirations, and invites readers to inquire into how rural populations negotiate and embrace, accommodate or reject rural transformations.

Monolithic integration of III–V semiconductors with Silicon technology has instigated a wide range of new possibilities in the semiconductor industry, such as combination of digital circuits with optical sensing and high-frequency communication. A promising CMOS compatible integration process is rapid melt growth (RMG) that can yield high quality single crystalline material at low cost. This paper represents the study on ultra-thin InSb-on-insulator microstructures integrated on a Si platform by a RMG-like process. We utilize flash lamp annealing (FLA) to melt and recrystallize the InSb material for an ultra-short duration (milliseconds), to reduce the thermal budget necessary for integration with Si technology. We compare the result from FLA to regular rapid thermal annealing (seconds). Recrystallized InSb was characterized using electron back scatter diffraction which indicate a transition from nanocrystalline structure to a crystal structure with grain sizes exceeding 1 μm after the process. We further see a 100× improvement in electrical resistivity by FLA annealed sample when compared to the as-deposited InSb with an average Hall mobility of 3100 cm2 V−1 s−1 making this a promising step towards realizing monolithic mid-infrared detectors and quantum devices based on InSb.

Enduring frontier spaces are key sites if one seeks to trace the subtle workings of power through the effects of the shifting rationalities of territorial governance. This article focuses on a particular group of people, the descendants of the first settler families to enter an area that would later become one of Argentina's flagship national parks. The figure of the settler occupied a shifting position within the racialized geographies of the protected areas of northwestern Patagonia, a remarkable descent from pioneers consolidating state-space to second-class citizens and tolerated squatters brought low by the institutionalization of precarity. The article asks what it means to be a descendant of settlers during the current period of multicultural recognition and the emergence of territorial claims based on indigenous identities in Argentina. It argues, that while the settlers within the protected area, the pobladores, hold a firm place in the territorial genealogy of Patagonia, they remain in these territories as relics of the past and are thus denied a meaningful existence within the Argentine settler state of the present. Contemporary maps of racialized power in the settler territories condition the politics of subject formation but are also met with resistance as settlers claim rights to full citizenship and recognition of their role as frontier pioneers and state space consolidators. Enduring frontier spaces are key sites if one seeks to trace the subtle workings of power through the effects of the shifting rationalities of territorial governance. This article focuses on a particular group of people, the descendants of the first settler families to enter an area that would later become one of Argentina's flagship national parks. The figure of the settler occupied a shifting position within the racialized geographies of the protected areas of northwestern Patagonia, a remarkable descent from pioneers consolidating state-space to second-class citizens and tolerated squatters brought low by the institutionalization of precarity. The article asks what it means to be a descendant of settlers during the current period of multicultural recognition and the emergence of territorial claims based on indigenous identities in Argentina. It argues, that while the settlers within the protected area, the pobladores, hold a firm place in the territorial genealogy of Patagonia, they remain in these territories as relics of the past and are thus denied a meaningful existence within the Argentine settler state of the present. Contemporary maps of racialized power in the settler territories condition the politics of subject formation but are also met with resistance as settlers claim rights to full citizenship and recognition of their role as frontier pioneers and state space consolidators.

III-V vertical nanowire MOSFETs (VNW-FETs) have the potential to extend Moore’s law owing to their excellent material properties. To integrate highly scaled memory cells coupled with high performance selectors at minimal memory cell area, it is attractive to integrate low-power resistive random access memory (RRAM) cells directly on to III-V VNW-FETs. In this work, we report the experimental demonstration of successful RRAM integration with III-V VNW-FETs. The combined use of VNW-FET drain metal electrode and the RRAM bottom electrode reduces the process complexity and maintains material compatibility. The vertical nanowire geometry allows the RRAM cell area to be aggressively scaled down to $0.01~\mu ^{m2}$ enabling realization of dense memory (1T1R) cross-point arrays on silicon.

The global proliferation of extraction and plantation economies continue to shape profoundly unequal exchanges of resources and labour and wreak havoc on rural economies, ecologies, and social relations. Yet, people at the receiving end of these transformations are not without agency. The spaces that are reshaped by the processes of violent accumulation are populated with individuals and communities who navigate the shifting economic, social, and political seas in the ongoing transformation of rural spaces. A recent special issue explores these processes and provides a conceptual approach with which we may understand how local people seek to make meaningful connections and disconnections to the capitalization of space, resources, and social relations. The global proliferation of extraction and plantation economies continue to shape profoundly unequal exchanges of resources and labor and wreak havoc on rural economies, ecologies, and social relations. Yet, people at the receiving end of these transformations are not without agency. The spaces that are reshaped by the processes of violent accumulation are populated with individuals and communities who navigate the shifting economic, social, and political seas in the ongoing transformation of rural spaces. A recent special issue explores these processes and provides a conceptual approach with which we may understand how local people seek to make meaningful connections and disconnections to the capitalization of space, resources, and social relations.

Peru’s peasant communities (comunidades campesinas) are collectivities organised around common land tenure. By tracing the development in organisation in a particular peasant community in highland Ancash, this article argues that the communally owned businesses were fundamental to the success of the community in its struggle to consolidate itself, and in the recovery of its ancestral lands. I explore emergent arenas of social struggle, arguing that these pivot around tensions between agrarian and non-agrarian business activities, the use of human and natural resources and, ultimately, local definitions of peasant identities, no longer rooted in agro-pastoral practices.

Resistive random access memory (RRAM) technologies based on non-volatile resistive filament redox switching oxides have the potential of drastically improving the performance of future mass-storage solutions. However, the physico-chemical properties of the TiN bottom metal electrode (BME) can significantly alter the resistive switching (RS) behavior of the oxygen-vacancy RRAM devices, yet the correlation between RS and the physico-chemical properties of TiN and HfOx/TiN interface remains unclear. Here, we establish this particular correlation via detailed material and electrical characterization for the purpose of achieving further performance enhancement of the stack integration. Two types of RRAM stacks were fabricated where the TiN BME was fabricated by physical vapor deposition (PVD) and atomic layer deposition (ALD), respectively. The HfOx layer in HfOx/PVD-TiN is more oxygen deficient than that of the HfOx/ALD-TiN because of more defective PVD-TiN and probably because pristine ALD-TiN has a thicker TiO2 overlayer. Higher concentration of oxygen vacancies induces a larger magnitude of band bending at the HfOx/PVD-TiN interface and leads to the formation of a higher Schottky barrier. Pulsed endurance measurements of up to 106 switches, with 10 μA ± 1.0 V pulses, demonstrate the potential of the studied ultra-thin-HfOx/TiN device stack for dense, large scale, and low-power memory integration.

The continuous scaling of electronic devices has brought Si based Complementary-Metal –Oxide-Semiconductor (CMOS) technology close to its limits, requiring novel materials and approaches to increase performance. Group III-V semiconductor nanowires have evolved as promising candidates due to their superior carrier mobility, saturation velocity and capability for bandgap engineering and integration in heterostructures, as well as their potential for use in active photonic devices. However, CMOS compatible, epitaxial integration of III-Vs on Si(100) remains challenging, mainly due to the formation of crystal defects, significantly reducing device performance. Selective Area Growth (SAG)1,2 and epitaxial lateral overgrowth (ELO)3–5 have both been demonstrated to reduce defects due to lattice mismatch. In a more recent method referred to as Template-Assisted Selective Epitaxy (TASE)6–10 nanostructures are grown entirely within pre-defined hollow template cavities containing a small Si seed, thus minimizing the...

GaSb nanostructures integrated on Si substrates are of high interest for p-type transistors and mid-IR photodetectors. Here, we investigate the metalorganic chemical vapor deposition and properties of GaSb nanostructures monolithically integrated onto silicon-on-insulator wafers using template-assisted selective epitaxy. A high degree of morphological control allows for GaSb nanostructures with critical dimensions down to 20 nm. Detailed investigation of growth parameters reveals that the GaSb growth rate is governed by the desorption processes of an Sb surface layer and, in turn, is insensitive to changes in material transport efficiency. The GaSb crystal structure is typically zinc-blende with a low density of rotational twin defects, and even occasional twin-free structures are observed. Hall/van der Pauw measurements are conducted on 20 nm-thick GaSb nanostructures, revealing high hole mobility of 760 cm2/(V s), which matches literature values for high-quality bulk GaSb crystals. Finally, we demonstrate a process that enables cointegration of GaSb and InAs nanostructures in close vicinity on Si, a preferred material combination ideally suited for high-performance complementary III-V metal-oxide-semiconductor technology.

Glacierized mountains are often referred to as our world's water towers because glaciers both store water over time and regulate seasonal stream flow, releasing runoff during dry seasons when societies most need water. Ice loss thus has the potential to affect human societies in diverse ways, including irrigation, agriculture, hydropower, potable water, livelihoods, recreation, spirituality, and demography. Unfortunately, research focusing on the human impacts of glacier runoff variability in mountain regions remains limited, and studies often rely on assumptions rather than concrete evidence about the effects of shrinking glaciers on mountain hydrology and societies. This article provides a systematic review of international research on human impacts of glacier meltwater variability in mountain ranges worldwide, including the Andes, Alps, greater Himalayan region, Cascades, and Alaska. It identifies four main areas of existing research: (1) socioeconomic impacts; (2) hydropower; (3) agriculture, irrigation, and food security; and (4) cultural impacts. The article also suggests paths forward for social sciences, humanities, and natural sciences research that could more accurately detect and attribute glacier runoff and human impacts, grapple with complex and intersecting spatial and temporal scales, and implement transdisciplinary research approaches to study glacier runoff. The objective is ultimately to redefine and reorient the glacier-water problem around human societies rather than simply around ice and climate. By systematically evaluating human impacts in different mountain regions, the article strives to stimulate cross-regional thinking and inspire new studies on glaciers, hydrology, risk, adaptation, and human–environment interactions in mountain regions.

Tunnel FETs (TFETs) have been identified as the most promising steep slope devices for ultralow power logic circuits. In this paper, we demonstrate in-plane InAs/Si TFETs monolithically integrated on Si, using our recently developed template-assisted selective epitaxy approach. These devices represent some of the most scaled TFETs with dimensions of less than 30 nm, combined with excellent aggregate performance with average subthreshold swing (SS), of around 70 mV/decade combined with $I_{\mathrm{\scriptscriptstyle ON}}$ of a few $\mu \text{A}$ / $\mu \text{m}$ for $|V_{\mathrm {\mathbf {DS}}}| = |V_{\mathrm {\mathbf {GS}}}| = 0.5$ V. Here, we will discuss the device fabrication as well as the experimental electrical data. Extensive low temperature characterization and activation energy analysis is used to gain insights into the factors limiting device performance. Combined with the simulation study presented in part 2 of this paper, this will elucidate how traps are ultimately limiting the SS.

This part of the paper presents TCAD simulations of the InAs/Si lateral nanowire (NW) tunnel FET (TFET) with the same geometry as the fabricated device discussed in the first part. In addition to band-to-band tunneling, trap-assisted tunneling (TAT) at the InAs/Si and InAs/oxide interfaces was considered. A very good agreement is found between the simulation results and experimental transfer characteristics of different devices. The simulations confirm that the transfer characteristics in the subthreshold regime of the TFETs are entirely dominated by TAT. Due to the high concentration of generation centers at the InAs/Si interface, the current conduction in the subthreshold regime takes place in two steps: carrier generation by TAT at the InAs/Si interface followed by thermionic emission over the hole barrier. The latter is the limiting process, and hence dominant for the subthreshold swing (SS), preventing a value smaller than 60mV/decade. In addition, traps at the Si/oxide interface reduce the electrostatic coupling between the gate and the channel, which further degrades the SS. Predictive simulations with varying interface trap densities indicate that a subthermal SS would only be achievable for $D_{\mathrm{ it}} cm $^{-2}$ eV $^{-1}$ at both InAs/Si and InAs/oxide interfaces. This confirms a recently found minimum requirement of $D_{\mathrm{ it}} cm $^{-2}$ eV $^{-1}$ for vertical InAs/Si NW TFETs with larger diameters.

Jason Antrosio & Rudi Colloredo-Mansfield: Fast, Easy, and In Cash. Artisan Hardship and Hope in the Global Economy Anmeldes af Mattias Borg Rasmussen

We present a low-temperature electrical transport study on four-terminal ballistic InAs nanowire cross-junctions in magnetic fields aligned perpendicular to the cross-plane. Two-terminal longitudinal conductance measurements between opposing contact terminals reveal typical 1D conductance quantization at zero magnetic field. As the magnetic field is applied, the 1D bands evolve into hybrid magneto-electric sub-levels that eventually transform into Landau levels for the widest nanowire devices investigated (width = 100 nm). Hall measurements in a four-terminal configuration on these devices show plateaus in the transverse Hall resistance at high magnetic fields that scale with (ve 2/h)−1. e is the elementary charge, h denotes Planck's constant and v is an integer that coincides with the Landau level index determined from the longitudinal conductance measurements. While the 1D conductance quantization in zero magnetic field is fragile against disorder at the NW surface, the plateaus in the Hall resistance at high fields remain robust as expected for a topologically protected Quantum Hall phase. (Less)

Glacial retreat reveals the unsettling effects of anthropogenic climate change, and challenges deeply seated cultural ideas about static landscapes. Glaciers have thus emerged as key signifiers of environmental loss. Because they are the outcomes of Westernized visions of the relationship between nature and culture, protected areas are important sites for understanding how notions of the Anthropocene come to reshape ideas about the future of glaciated landscapes. This article explores one particular conservation initiative, that of the establishment of the tourist and educational facility known as the Route of Climate Change in Peru’s Huascarán National Park. It asks how we can understand the production of conservation landscapes in a context where the framing of glaciers as an endangered species denies their fluctuating dynamics and imparts to them a directionality toward irreversible change. Focusing on the contentious production of conservation landscapes through interaction between the park administration and a local community, the article is based on ethnographic fieldwork consisting of semi-structured interviews (48), informal conversations, and participant observation over multiple visits to the area between 2013 and 2015. The study finds that while the production of new conservation narratives certainly resituates the sites in time and place, it also produces uncertain environmental futures that may be molded to secure a rapprochement between park administrations and communities based on mutual alignment of conservation and community practices. It is thus argued that an underlying shift in orientation—from preserving what is to countering what might otherwise come to be—results in the production of new imaginaries about conservation landscapes that are both a condition and an outcome of protected area management in times of glacial retreat.

InGaAs is a potential candidate for Si replacement in upcoming advanced technological nodes because of its excellent electron transport properties and relatively low interface defect density in dielectric gate stacks. Therefore, integrating InGaAs devices with the established Si platforms is highly important. Using template-assisted selective epitaxy (TASE), InGaAs nanowires can be monolithically integrated with high crystal quality, although the mechanisms of group III incorporation in this ternary material have not been thoroughly investigated. Here we present a detailed study of the compositional variations of InGaAs nanostructures epitaxially grown on Si(111) and Silicon-on-insulator substrates by TASE. We present a combination of XRD data and detailed EELS maps and find that the final Ga/In chemical composition depends strongly on both growth parameters and the growth facet type, leading to complex compositional sub-structures throughout the crystals. We can further conclude that the composition is governed by the facet-dependent chemical reaction rates at low temperature and low V/III ratio, while at higher temperature and V/III ratio, the incorporation is transport limited. In this case we see indications that the transport is a competition between Knudsen flow and surface diffusion.

Herein, an optimized process flow of near-surface quantum well metal–oxide–semiconductor field-effect transistors (MOSFETs) based on planar layers of metalorganic vapor-phase epitaxy (MOVPE) grown InxGa1−xAs is presented. It is found that by an optimized pre-growth cleaning and post-metal anneal, the quality of the MOS structure can be greatly enhanced. This optimization is a first step toward realization of a scalable platform for topological qubits based on a well-defined network of lateral InxGa1−xAs nanowires grown by selective area growth.

We propose a capacitance measurement scheme that enables quantitative characterization of ferroelectric thin films integrated on semiconductors. The film defect density is estimated by measurements of the CV hysteresis and frequency dispersion, whereas important device parameters such as memory window and endurance can be extracted by a unidirectional CV method. The simple measurement scheme and the usage of metal-oxide-semiconductor capacitors rather than MOSFETs make the proposed methods suitable for the future optimization of ferroelectric field effect transistor and negative capacitance field effect transistor gate stacks. Specifically, we present data for the narrow bandgap semiconductor InAs and show that low temperature characterization is critical to reduce the influence of the minority carrier response; however, the methods should be transferrable to room temperature for semiconductors with a wider bandgap. Our results clearly indicate that the defect density of the HfxZr1−xO2 (HZO) films increases at the crystallization temperature, but the increase is modest and remains independent of the annealing temperature at even more elevated temperatures. It is also shown that the shrinkage of the memory window caused by field cycling is not accompanied by an increase in defect density.

We present experimental data on the time and radius-dependent length distributions of Au-catalyzed InAs nanowires grown by metal organic vapor phase epitaxy. We show that these distributions are not as sharp as commonly believed. Rather, they appear to be much broader than Poissonian from the very beginning and spread quickly as the nanowires grow. We develop a model that attributes the observed broadening to the diffusion-induced character of growth. In the initial growth stage, the nanowires are fed from their entire length, leading to a Polya-like length distribution whose standard deviation is proportional to the mean length. After the nanowire length exceeds the adatom diffusion length, the growth acquires a Poissonian character in which the standard deviation scales as a square root of the mean length. We explain why wider nanowires have smaller length dispersion and speculate on the length distributions in Au-catalyzed versus self-catalyzed growth methods.