Galo A Torres Sevilla

• PhD
• King Abdullah University of Science and Technology

Flexible electronics are integral in numerous domains such as wearables, healthcare, physiological monitoring, human–machine interface, and environmental sensing, owing to their inherent flexibility, stretchability, lightweight construction, and low profile. These systems seamlessly conform to curvilinear surfaces, including skin, organs, plants, r...

Perovskite‐Cu(In,Ga)Se2 (CIGS) thin‐film tandem technology provides an exciting prospect to achieve low‐cost high‐efficiency photovoltaic devices by high throughput roll‐to‐roll processing on flexible substrates. However, no report on flexible perovskite‐CIGS mini‐modules has been published due to scribing related challenges in realizing NIR‐transp...

Here, we propose a method to create a transparent security system based on printed conductive indium tin oxide (ITO)—the most widely used transparent conducting oxide material integrated into the devices with high transparency. Commonly used solution-processed ITO annealing methods are utilizing temperatures which are limiting the use of flexible p...

The rapid evolution of the neuromorphic computing stimulates the search for novel brain-inspired electronic devices. Synaptic transistors are three-terminal devices that can mimic the chemical synapses while consuming low power, whereby an insulating dielectric layer physically separates output and input signals from each other. Appropriate choice...

Indium tin oxide (ITO) is a transparent conducting material that is widely used in devices where high transparency of the electrodes is required, such as flat panel and liquid crystal displays, touch panels, smart windows, and many others. ITO layers are deposited on a large scale by magnetron sputtering and then structured by lithography to define...

The fabrication of solution-processed electronic devices based on amorphous In–Ga–Zn–O (a-IGZO) requires high-temperature post-deposition annealing to activate IGZO layers and minimize impurities. Deep-ultraviolet (DUV) treatment can reduce the post-deposition annealing temperature when manufacturing a-IGZO thin-film transistors. Here, we investiga...

Amorphous In-Ga-Zn-O (IGZO) is a high-mobility semiconductor employed in modern thin-film transistors for displays and it is considered as a promising material for Schottky diode-based rectifiers. Properties of the electronic components based on IGZO strongly depend on the manufacturing parameters such as the oxygen partial pressure during IGZO spu...

State‐of‐the‐art Cu(In,Ga)Se2 (CIGS) solar cells are grown with considerably substoichiometric Cu concentrations. The resulting defects, as well as potential improvements through increasing the Cu concentration, have been known in the field for many years. However, so far, cells with high Cu concentrations show decreased photovoltaic parameters. In...

Recent developments in inkjet printing have shown it to be a viable method for low‐cost and large‐area coating of oxide materials. In article 1800843, S. Bolat et al. report the low‐temperature synthesis of yttrium aluminum oxide (YAlOx) dielectric layers through a combination of inkjet printing of sol–gel precursors and heat‐assisted deep ultravio...

Recent developments in inkjet printing have proven it a viable method for low‐cost and large‐area coating of oxide materials. The main drawback of this method is the common requirement of a post‐deposition annealing (PDA) of the printed layers at relatively high temperatures (T > 200 °C). This sets a requirement for the substrate to have high glass...

Current marine research primarily depends on weighty and invasive sensory equipment and telemetric network to understand the marine environment, including the diverse fauna it contains, as a function of animal behavior and size, as well as equipment longevity. To match animal morphology and activity within the surrounding marine environment, here w...

Imaging is one of the important wonders of today’s world. While everyday millions of snaps are taken, new advances like panoramic imaging becomes increasingly popular. However, as of today an imaging system which can simultaneously capture images from all 360° viewpoints with a single sensor has not been achieved yet. Here, we show a physically fle...

Nearly sixty years back when Jack Kilby built the first integrated circuit (IC), it was also the beginning of today's advanced and matured complementary metal oxide semiconductor (CMOS) technology whose arts and science of miniaturization has enabled Moore's Law to double up the number of devices in a given area in every two years. It has also been...

Reconfigurable electronics is a new class of electronics which can change their shape and sizes as needed. We discuss integration strategy (design, choice of materials, process integration, characterization and optimization) of such electronics for display and healthcare applications.

Flexible electronics is an emerging field in many applications ranging from in vivo biomedical devices to wearable smart systems. The capability of conforming to curved surfaces opens the door to add electronic components to miniaturized instruments, where size and weight are critical parameters. Given their prevalence on the sensors market, flexib...

In article number 1702221, Muhammad M. Hussain and co‐workers demonstrate corrugation architecture enabled ultra‐flexible (140 mm bending radius), high performance (17.2% photovoltaic efficiency) crystalline silicon solar cells (each cell area 1276.2 mm²) on a five‐inch wafer via a lithography‐less Complementary Metal Oxide Semiconductor (CMOS) com...

Advanced classes of modern application require new generation of versatile solar cells showcasing extreme mechanical resilience, large-scale, low cost, and excellent power conversion efficiency. Conventional crystalline silicon-based solar cells offer one of the most highly efficient power sources, but a key challenge remains to attain mechanical r...

Thermoelectricity can be an interesting source of power from otherwise wasted heat. Therefore, for many decades discovery and optimization of new thermoelectric materials has shown important leap toward thermoelectric generator applications. However, from an engineering perspective, structural modifications at the device level can play an important...

In today's digital age, the increasing dependence on information also makes us vulnerable to potential invasion of privacy and cyber security. Consider a scenario in which a hard drive is stolen, lost, or misplaced, which contains secured and valuable information. In such a case, it is important to have the ability to remotely destroy the sensitive...

The state-of-the-art electronics technology has been an integral part of modern advances. The prevalent rise of the mobile device and computational technology in the age of information technology offers exciting applications that are attributed to sophisticated, enormously reliable, and most mature CMOS-based electronics. We are accustomed to high...

As we are advancing our world to smart living, a critical challenge is increasingly pressing - increased energy demand. While we need mega power supplies for running data centers and other emerging applications, we also need instant small-scale power supply for trillions of electronics that we are using and will use in the age of Internet of Things...

In article number 1600175, Muhammad M. Hussain and co-workers report a highly manufacturable heterogeneous integration strategy to combine complementary metal oxide semiconductor electronics, inkjet printing for interconnection, 3D printing for packaging, and roll-to-roll printing of decal electronics. The flexible electronic system shows reliable...

We report CMOS technology enabled fabrication and system level integration of flexible bulk silicon (100) based multi-sensors platform which can simultaneously sense pressure, temperature, strain and humidity under various physical deformations. We also show an advanced wearable version for body vital monitoring which can enable advanced healthcare...

Affordable and versatile printed electronics can play a critical role for large area applications, such as for displays, sensors, energy harvesting, and storage. Significant advances including commercialization in the general area of printed electronics have been based on organic molecular electronics. Still some fundamental challenges remain: ther...

High-performance complementary metal oxide semiconductor electronics are flexed, packaged using 3D printing as decal electronics, and then printed in roll-to-roll fashion for highly manufacturable printed flexible high-performance electronic systems.

We present a comprehensive electrical performance assessment of hafnium silicate (HfSiOₓ) high-κ dielectric and titanium-nitride (TiN) metal-gate-integrated FinFET-based complementary-metal-oxide-semiconductor (CMOS) on flexible silicon on insulator. The devices were fabricated using the state-of-the-art CMOS technology and then transformed into fl...

Using low-cost recyclable household materials such as paper and aluminum foil, Muhammad M. Hussain and co-workers construct a paper-based artificial skin in article 1600004. The flexible platform comprises a 3D-stacked architecture, with an array of multi-purpose pressure, temperature, and humidity sensors. The paper skin is capable of simultaneous...

Thinned silicon based complementary metal oxide semiconductor(CMOS)electronics can be physically flexible. To overcome challenges of limited thinning and damaging of devices originated from back grinding process, we show sequential reactive ion etching of silicon with the assistance from soft polymeric materials to efficiently achieve thinned (40 μ...

Human skin and hair can simultaneously feel pressure, temperature, humidity, strain, and flow—great inspirations for applications such as artificial skins for burn and acid victims, robotics, and vehicular technology. Previous efforts in this direction use sophisticated materials or processes. Chemically functionalized, inkjet printed or vacuum-tec...

In today's digital world, complementary metal oxide semiconductor (CMOS) technology enabled scaling of bulk mono-crystalline silicon (100) based electronics has resulted in their higher performance but with increased dynamic and off-state power consumption. Such trade-off has caused excessive heat generation which eventually drains the charge of ba...

Flexibility can bring a new dimension to state-of-the-art electronics, such as rollable displays and integrated circuit systems being transformed into more powerful resources. Flexible electronics are typically hosted on polymeric substrates. Such substrates can be bent and rolled up, but cannot be independently fixed at the rigid perpendicular pos...

Future wearable electronics require not only flexibility but also preservation of the perks associated with today's high-performance, traditional silicon electronics. In this work we demonstrate a state-of-the-art fin-shaped field-effect transistor (FinFET)-based, out-of-plane strain sensor on flexible silicon through transforming the bulk device i...

We report out-of-plane strain effect on silicon based flexible FinFET, with sub 20 nm wide fins and hafnium silicate based high-κ gate dielectric. Since ultra-thin inorganic solid state substrates become flexible with reduced thickness, flexing induced strain does not enhance performance. However, detrimental effects arise as the devices are subjec...

We show the effectiveness of wavy channel architecture for thin film transistor application for increased output current. This specific architecture allows increased width of the device by adopting a corrugated shape of the substrate without any further real estate penalty. The performance improvement is attributed not only to the increased transis...

Current developments on enhancing our smart living experience are leveraging the increased interest for novel systems that can be compatible with foldable, wrinkled, wavy and complex geometries and surfaces, and thus become truly ubiquitous and easy to deploy. Therefore, relying on innovative structural designs we have been able to reconfigure the...

Based on the Joule heating principle, a wirelessly controlled thermal patch is developed on page 665 for pain management which uses low-cost copper as the functional material in a serpentine-shaped fractal design to vary the size of the patch based on pain location. Complementary metal oxide semiconductor technology is used by M. M. Hussain and co-...

Unprecedented 800% stretchable, non-polymeric, widely used, low-cost, naturally rigid, metallic thin-film copper (Cu)-based flexible and non-invasive, spatially tunable, mobile thermal patch with wireless controllability, adaptability (tunes the amount of heat based on the temperature of the swollen portion), reusability, and affordability due to l...

We report the temperature dependence of the core electrical parameters and transport characteristics of a flexible version of fin field-effect transistor (FinFET) on silicon-on-insulator (SOI) with sub-20-nm wide fins and high-k/metal gate-stacks. For the first time, we characterize them from room to high temperature (150 °C) to show the impact of...

We demonstrate a flexible version of the semiconductor industry's most advanced transistor topology - FinFET on silicon-on-insulator (SOI) with sub-20 nm fins and high-κ/metal gate stacks. This is the most advanced flexible (0.5 mm bending radius) transistor on SOI ever demonstrated for exciting opportunities in high performance flexible electronic...

We report high temperature electrical transport characteristics of a flexible version of the semiconductor industry's most advanced architecture: fin field-effect transistor on silicon-on-insulator with sub-20nm fins and high-kappa/metal gate stacks. Characterization from room to high temperature (150 degrees C) was completed to determine temperatu...

We report a new Thin Film Transistor (TFT) architecture that allows expansion of the device width using wavy (continuous without separation) fin features - termed as wavy channel (WC) architecture. This architecture allows expansion of transistor width in a direction perpendicular to the substrate, thus not consuming extra chip area, achieving area...

With the emergence of cloud computation, we are facing the rising waves of big data. It is our time to leverage such opportunity by increasing data usage both by man and machine. We need ultra-mobile computation with high data processing speed, ultra-large memory, energy efficiency and multi-functionality. Additionally, we have to deploy energy-eff...

Evolution in transistor technology from increasingly large power consuming single gate planar devices to energy efficient multiple gate non-planar ultra-narrow (< 20 nm) fins has enhanced the scaling trend to facilitate doubling performance. However, this performance gain happens at the expense of arraying multiple devices (fins) per operation bit,...

Brain's stunning speed, energy efficiency and massive parallelism makes it the role model for upcoming high performance computation systems. Although human brain components are a million times slower than state of the art silicon industry components [1], they can perform 1016 operations per second while consuming less power than an electrical light...

We demonstrate the first ever CMOS compatible soft etch back based high performance flexible CMOS SOI FinFETs. The move from planar to non-planar FinFETs has enabled continued scaling down to the 14 nm technology node. This has been possible due to the reduction in off-state leakage and reduced short channel effects on account of the superior elect...

The brain's cortex is folded and thus can accommodate billions of neurons in an ultra-compact area. On page 2794, M. M. Hussain and co-workers demonstrate the world's first state-of-the-art non-planar 3D FinFET on flexible silicon-on-polymer using a CMOS compatible process to enable brain-architecture-inspired future ultra-high performance electron...

A low-cost simple thin film deposition of tin (Sn), followed by thermal annealing based alloying of it into the silicon channel, leads to an enhancement of the performance of silicon-based CMOS devices. Modelling based on density functional theory (DFT) shows that Sn incorporation may lower the band gap of the silicon channel, while the experimenta...

We explore the effectiveness of tin (Sn), by alloying it with silicon, to use SiSn as a channel material to extend the performance of silicon based complementary metal oxide semiconductors. Our density functional theory based simulation shows that incorporation of tin reduces the band gap of Si(Sn). We fabricated our device with SiSn channel materi...

We demonstrate a new thin film transistor (TFT) architecture that allows expansion of the device width using continuous fin features – termed as wavy channel (WC) architecture. This architecture allows expansion of transistor width in a direction perpendicular to the substrate, thus not consuming extra chip area, achieving area efficiency. The devi...

Flexible and transparent high performance thermoelectric energy harvesters from low cost bulk silicon wafers are fabricated using existing silicon processes on silicon (100) and then peeled off from the original substrate leaving it for reuse. As reported on page 3916 by M. M. Hussain and co-workers, the peeled off silicon has 3.6% thickness of bul...

We demonstrate a simple, low-cost, and scalable process for obtaining uniform, smooth surfaced, high quality mono-crystalline germanium (100) thin films on silicon (100). The germanium thin films were deposited on a silicon substrate using plasma-assisted sputtering based physical vapor deposition. They were crystallized by annealing at various tem...

Germanium is a historical semiconductor material whose hole mobility is much higher than that in silicon. Its near-term application areas include, but are not limited to, p-type metal oxide semiconductor field effect transistors (p-MOSFETs) in complementary metal oxide semiconductor (CMOS) technology, high speed devices for communications and optoe...

We study a group IV element: tin (Sn) by integrating it into silicon lattice, to enhance the performance of silicon CMOS. We have evaluated the electrical properties of the SiSn lattice by performing simulations using First-principle studies, followed by experimental device fabrication and characterization. We fabricated high-κ/metal gate based Met...

State-of-the art computers need high performance transistors, which consume ultra-low power resulting in longer battery lifetime. Billions of transistors are integrated neatly using matured silicon fabrication process to maintain the performance per cost advantage. In that context, low-cost mono-crystalline bulk silicon (100) based high performance...

This paper reports a generic process flow to fabricate mechanically flexible and optically semi-transparent thermoelectric generators (TEGs), micro lithium-ion batteries (μLIB) and metal-oxide-semiconductor capacitors (MOSCAPs) on mono-crystalline silicon fabric platforms from standard bulk silicon (100) wafers. All the fabricated devices show outs...

We present a novel semiconducting alloy, Silicon-tin (SiSn), as a channel material for LSTP device applications. The diffusion of Sn into silicon has been explored to demonstrate, for the first time, a MOSFET using SiSn as channel material. The semiconducting alloy SiSn offers interesting possibilities in the realm of silicon bandgap tuning and str...

Today’s information age is driven by silicon based electronics. For nearly four decades semiconductor industry has perfected the fabrication process of continuingly scaled transistor – heart of modern day electronics. In future, silicon industry will be more pervasive, whose application will range from ultra-mobile computation to bio-integrated med...

We report a wavy channel FinFET like transistor where the channel is wavy to increase its width without any area penalty and thereby increasing its drive current. Through simulation and experiments, we show the effectiveness of such device architecture is capable of high performance operation compared to conventional FinFETs with comparatively high...

Tungsten disulfide (WS2) is a layered transition metal dichalcogenide with a reported band gap of 1.8 eV in bulk and 1.32-1.4 eV in its thin film form. 2D atomic layers of metal dichalcogenides have shown changes in conductivity with applied electric field. This makes them an interesting option for channel material in field effect transistors (FETs...

In pursuit of flexible computers with high performance devices, we demonstrate a generic process to fabricate 10 000 metal-oxide-semiconductor capacitors (MOSCAPs) with semiconductor industry's most advanced high-k/metal gate stacks on widely used, inexpensive bulk silicon (100) wafers and then using a combination of iso-/anisotropic etching to rel...