Satadal Dutta - Academia.edu (original) (raw)

Papers by Satadal Dutta

Optics Express

We report on the effect of Fabry-Pérot (FP) resonance on hot-carrier electroluminescence (EL) spe... more We report on the effect of Fabry-Pérot (FP) resonance on hot-carrier electroluminescence (EL) spectra and the optical power efficiencies of silicon (Si) avalanche-mode (AM) LEDs in the wavelength range from 500 nm to 950 nm. The LEDs, fabricated in a silicon-on-insulator photonics technology, consist of symmetric p-n junctions placed within a 0.21 µm thick Si micro-ring of varying width and radius. We show that the peak wavelength in the EL-spectra can be tuned within a range of 100 nm by varying the ring width from 0.16 µm to 0.30 µm, which is explained by FP resonance. The measured EL-spectra features relatively narrow bands (with a spectral width of ∼50 nm) with high intensities compared to conventional Si AMLEDs. By varying the ring radius and using a high doping level, we obtain a record high optical power efficiency of 3.2×10−5. Our work is a breakthrough in engineering the EL spectrum of Si, foreseen to benefit the performance of Si-integrated optical interconnects and sensors.

Research

Although it is well known that plants emit acoustic pulses under drought stress, the exact origin... more Although it is well known that plants emit acoustic pulses under drought stress, the exact origin of the waveform of these ultrasound pulses has remained elusive. Here, we present evidence for a correlation between the characteristics of the waveform of these pulses and the dimensions of xylem conduits in plants. Using a model that relates the resonant vibrations of a vessel to its dimension and viscoelasticity, we extract the xylem radii from the waveforms of ultrasound pulses and show that these are correlated and in good agreement with optical microscopy. We demonstrate the versatility of the method by applying it to shoots of ten different vascular plant species. In particular, for Hydrangea quercifolia , we further extract vessel element lengths with our model and compare them with scanning electron cryomicroscopy. The ultrasonic, noninvasive characterization of internal conduit dimensions enables a breakthrough in speed and accuracy in plant phenotyping and stress detection.

Although it is well known that plants emit acoustic pulses under drought stress, the exact origin... more Although it is well known that plants emit acoustic pulses under drought stress, the exact origin of the waveform of these ultrasound pulses has remained elusive. Here we present evidence for a correlation between the characteristics of the waveform of these pulses and the dimensions of xylem vessels in plants. Using a model that relates the resonant vibrations of a vessel to its dimension and viscoelasticity, we extract the xylem radii from the waveforms of ultrasound pulses and show that these are correlated and in good agreement with optical microscopy. We demonstrate the versatility of the method by applying it to shoots of ten different vascular plant species. In particular, for Hydrangea quercifolia, we further extract vessel element lengths with our model and compare them with scanning electron cryo-microscopy. The ultrasonic, non-invasive characterization of internal vessel dimensions enables a breakthrough in speed and accuracy in plant phenotyping and stress-detection.

&lt;p&gt;Plant transpiration accounts for about half of all terrestrial evaporati... more &lt;p&gt;Plant transpiration accounts for about half of all terrestrial evaporation (Jasechko et al., 2013). Plants need water for many vital functions including nutrient uptake, growth, maintenance of cell turgor pressure and leaf cooling. Due to the regulation of water transport by stomata in the leaves, plants lose 97% of the water they take via their roots, to the atmosphere. They can be viewed as transpiration-powered pumps on the interface between the soil and atmosphere.&lt;/p&gt;&lt;p&gt;Measuring plant-water dynamics is essential to gain better insight into their role in the terrestrial water cycle and plant productivity. It can be measured at different levels of integration, from the single cell micro-scale to the ecosystem macro-scale, on time scales from minutes to months. In this contribution, we give an overview of state-of-the-art techniques for transpiration measurement and highlight several promising innovations for monitoring plant-water relations. Some of the techniques we will cover include stomata imaging by microscopy, gas exchange for stomatal conductance and transpiration monitoring, thermometry for water stress detection, sap flow monitoring, hyperspectral imaging, ultrasound spectroscopy, accelerometry, scintillometry and satellite-remote sensing.&lt;/p&gt;&lt;p&gt;Outlook: To fully assess water transport within the soil-plant-atmosphere continuum, a variety of techniques is required to monitor environmental variables in combination with biological responses at different scales. Yet this is not sufficient: to truly solve for spatial heterogeneity as well as temporal variability, dense network sampling is needed.&lt;/p&gt;&lt;p&gt;In PLANTENNA (https://www.4tu.nl/plantenna/en/) a team of electronics, precision and microsystems engineers together with plant and environmental scientists develop and implement innovative (3D-)sensor networks that measure plant and environmental parameters at high resolution and low cost. Our main challenge for in-situ sensor autonomy (&amp;#8220;plug and forget&amp;#8221;) is energy: we want the sensor nodes to be hyper-efficient and rely fully on (miniaturised) energy-harvesting.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;REFERENCES: &lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Jasechko, S., Sharp, Z. D., Gibson, J. J., Birks, S. J., Yi, Y., &amp; Fawcett, P. J. (2013). Terrestrial water fluxes dominated by transpiration. Nature, 496(7445), 347-350.&lt;br&gt;Plantenna: "Internet of Plants". (n.d.). https://www.4tu.nl/plantenna/en/&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

IEEE Electron Device Letters

We report an avalanche-mode light-emitting transistor (AMLET) in silicon (Si), based on a lateral... more We report an avalanche-mode light-emitting transistor (AMLET) in silicon (Si), based on a lateral bipolar junction, which emits light near 760 nm optical wavelength with a record low bandwidth of 38 nm. The AMLET, designed in a CMOS-compatible silicon-on-insulator (SOI) photonics platform, is optically confined within a 0.21 µm thick SOI layer, which forms a Fabry-Pérot (FP) resonator perpendicular to the Si surface. Light is emitted from the reverse biased emitter-base junction via phonon-assisted hot carrier recombination and, additionally, minority carriers are injected via the forward-biased Base-Collector junction. The combination of injection from collector terminal through a narrow base and FP optical resonance, yields a high optical power efficiency of 4.3×10 −6 at V BC = 0.8 V and V EB = 10 V. Our work opens new possibilities in spectralengineering of Si light-emitters, which could boost performance of all-Si optical interconnects and sensors.

IEEE Electron Device Letters

The CMOS silicon avalanche-mode lightemitting diode (AMLED) has emerged as a potential light sour... more The CMOS silicon avalanche-mode lightemitting diode (AMLED) has emerged as a potential light source for monolithic optical interconnects. Earlier we presented a superjunction light-emitting diode (SJLED) that offers a higher electroluminescent intensity compared to a conventional AMLED because of its more uniform field distribution. However, for reducing power consumption lowvoltage (≤15V) SJLEDs are desired, not explored before. In this work we present a TCAD simulation feasibility study of the low-voltage SJLED for various doping concentrations and device dimensions. The results show that for obtaining a constant field, approximately a tenfold more aggressive charge balance condition in the SJLED is estimated than traditionally reported. This is important for establishing a guideline to realize optimized RESURF and SJLEDs in the ever-shrinking advanced CMOS nodes.

Small and low-cost chlorophyll sensors are popular in agricultural sector and food-quality contro... more Small and low-cost chlorophyll sensors are popular in agricultural sector and food-quality control. Combining such sensors with silicon CMOS electronics is challenged by the absence of silicon-integrated light-sources. We experimentally achieve optical absorption sensing of chlorophyll based pigments with silicon (Si) micro light-emitting diodes (LED) as light-source, fabricated in a standard SOI-CMOS technology. By driving a Si LED in both forward and avalanche modes of operation, we steer its electroluminescent spectrum between visible (400–900 nm) and near-infrared (~1120 nm). For detection of chlorophyll in solution phase, the dual-spectrum light from the LED propagates vertically through glycerol micro-droplets containing sodium copper chlorophyllin at varying relative concentrations. The transmitted light is detected via an off-chip Si photodiode. The visible to near-infrared color ratio (COR) of the photocurrent yields the effective absorption coefficient. We introduce the LE...

2020 IEEE SENSORS, 2020

Silicon p-n junction diodes emit low-intensity, broad-spectrum light near 1120 nm in forward bias... more Silicon p-n junction diodes emit low-intensity, broad-spectrum light near 1120 nm in forward bias and between 400-900 nm in reverse bias (avalanche). For the first time, we experimentally achieve optical absorption sensing of pigment in solution with silicon micro LEDs designed in a standard silicon-on-insulator CMOS technology. By driving a single LED in both forward and avalanche modes of operation, we steer it's electroluminescent spectrum between visible and near-infrared (NIR). We then characterize the vertical optical transmission of both visible and NIR light from the LED through the same micro-droplet specimen to a vertically mounted discrete silicon photodiode. The effective absorption coefficient of carmine solution in glycerol at varying concentrations were extracted from the color ratio in optical coupling. By computing the LED-specific molar absorption coefficient of carmine, we estimate the concentration (~0.040 mol L-1) and validate the same with a commercial spectrophotometer (~0.030 mol L-1). With a maximum observed sensitivity of ~1260 cm-1 mol-1 L, the sensor is a significant step forward towards low-cost CMOS-integrated optical sensors with silicon LED as the light source intended for biochemical analyses in food sector and plant/human health.

Fifth Conference on Sensors, MEMS, and Electro-Optic Systems, 2019

The light emission from silicon PureB photodiodes was investigated in both forward- and avalanche... more The light emission from silicon PureB photodiodes was investigated in both forward- and avalanchemode operation and correlated to the presence of process-dependent defects that influence the reverse IV characteristics. As opposed to “defect-free” diodes with low dark currents and abrupt breakdown behavior, the diodes with defects had higher current levels and light-emitting spots appearing at voltages far below the breakdown voltage otherwise set by the implemented doping profiles. The role of such defect-related behavior for the application of the photodiodes as single-photon avalanche diodes (SPADs) and avalanche-mode light-emitting diodes (AMLEDs) is assessed in connection with the recent demonstration of these basic devices as both the light-emitting and light-detecting elements in optocoupler circuits integrated in CMOS for data transmission purposes.

The silicon avalanche-mode light-emitting diode (AMLED) opens a route for on-chip opto-electronic... more The silicon avalanche-mode light-emitting diode (AMLED) opens a route for on-chip opto-electronic applications in standard CMOS, both due to its relatively broad spectral overlap with the spectral responsivity of silicon photodiodes and due to its high speed capability. This work presents closed form models for the key figures of merit (FOMs) of AMLEDs, namely, current (or power) density, cut-off frequency, radiative efficiency, and specifically for optical data communication energy cost per photon. Their derivations are based on one-dimensional analyses of an abrupt single-sided (p+n or n+p) junction and of a p-i-n diode. TCAD simulations for optimized device structures, including the recently reported superjunction (SJ) LED, were performed to validate the model. Measurements on single-sided abrupt junctions and SJ diodes are shown to validate some of the modelled trends. The results show that a p-i-n or an SJ diode is favorable to a conventional single-sided junction diode for the...

Although it is well known that plants emit ultrasound bursts under drought stress, the exact orig... more Although it is well known that plants emit ultrasound bursts under drought stress, the exact origin of the acoustic waveform of these pulses has remained elusive. Here we present evidence for a correlation between the ultrasound spectrum of these pulses and the dimensions of the plant’s xylem vessels. Using a model that relates the vibrational excitations of the vessels to their geometric and viscoelastic properties, we develop a methodology to extract the internal xylem vessel dimensions from recorded ultrasound waveforms. We apply the method to ultrasound pulses from drying shoots of three vascular dicot plant species, and validate it by comparison with destructive measurements via microscopy. Our method demonstrates the potential for continuous monitoring of the vascular anatomy of plants. The ultrasonic, non-invasive characterization of internal vessel dimensions can lead to breakthroughs in speed and accuracy in plant phenotyping and disease detection in agriculture.

2017 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD), 2017

A TCAD based analysis is presented on the transmission efficiency η of silicon-on-insulator (SOI)... more A TCAD based analysis is presented on the transmission efficiency η of silicon-on-insulator (SOI) and silicon nitride slab waveguides in a high-voltage standard SOI-CMOS technology, for the spectral range of 480 nm–1300 nm, and isotropic optical excitation via monolithic Si-based LEDs. The effects of geometry, wavelength and galvanic isolation on η are reported.

Plants emit ultrasound pulses under drought stress, which originate in their water-carrying xylem... more Plants emit ultrasound pulses under drought stress, which originate in their water-carrying xylem vessels, and can be recorded externally. We demonstrate that these ultrasound pulses consist of superposed damped oscillations at plant-specific frequencies in the range of 10 – 150 kHz, that are correlated to xylem dimensions. We present a method to relate geometrical and viscoelastic properties of xylem vessels with the time- and frequency-domain characteristics of the observed oscillations. We apply the method to ultrasound pulses from drying shoots of three vascular dicot plant species. The extracted parameters are validated with destructive measurements of xylem vessel radii, wall thickness, length of xylem vessel elements, and the elastic modulus of the vascular bundle by optical and scanning cryo-electron microscopy and tensile loading. Our method demonstrates the potential for non-invasive and continuous monitoring of plant vascular anatomy. We foresee applications in high-throu...

IEEE Transactions on Electron Devices, 2018

In this paper, we investigate the presence of minority carriers and their role in charge carrier ... more In this paper, we investigate the presence of minority carriers and their role in charge carrier transport in silicon (Si) Schottky diodes with a high potential barrier. Using TCAD simulations along with an analytical model, we show that an inversion charge is induced at the metal-semiconductor (MS) interface in a high-barrier Schottky diode which imparts bipolar-type current characteristics to otherwise a unipolar Schottky diode, even at low-injection operation. In such a high-barrier diode, minority diffusion also becomes important along with the majority carrier thermionic emission and therefore cannot be neglected, unlike in a conventional Schottky diode. The presence of minority carriers at low injection in a high-barrier Si Schottky diode has been experimentally verified via a prior-reported two-diode electrical test method, reverse recovery measurements, and by measuring infrared electroluminescence. It is also shown, via TCAD simulations, that the diffusion component becomes more pronounced in case of a reduced Gummel number and at elevated temperatures.

IEEE Transactions on Electron Devices, 2018

The data transmission capabilities of silicon avalanche mode light-emitting diodes (AMLEDs) were ... more The data transmission capabilities of silicon avalanche mode light-emitting diodes (AMLEDs) were investigated and the results are correlated to the multiplication noise and leakage current. The incoming data were modulated using pulse position modulation and the bit-error-rate (BER) and jitter in the transmitted data were measured. The results indicate an intrinsically low speed in terms of BER and jitter. From various size AMLEDs, temperature variations and optical excitations, it is shown that the speed can be improved by using AMLEDs with a (1) relatively high multiplication noise, (2) relatively high leakage current and (3) higher charge-per-bit. Design recommendations for the high speed AMLEDs are discussed.

IEEE Journal of the Electron Devices Society, 2018

An extensive time domain analysis of the random telegraph signal (RTS) phenomena in silicon avala... more An extensive time domain analysis of the random telegraph signal (RTS) phenomena in silicon avalanche diodes is presented. Experiments show two distinct types of RTSs classified herein, on the basis of the temporal behavior of the amplitude, as the "decaying" and the "constant" type. These RTSs are analyzed using a model for defects reported earlier, from which their ohmic series resistance and geometrical parameters have been estimated. The results indicate that breakdown of a relatively small area defect results in a "decaying" amplitude type of RTS, and breakdown of a relatively large area defect results in a "constant" amplitude type of RTS. These two types can be explained by the differences in the thermal resistance, which is higher for the former. INDEX TERMS Avalanche breakdown, avalanche diodes, microplasma, random telegraph noise, random telegraph signal, time domain analysis.

$Research paper thumbnail of Composite GaN–C–Ga (“GaCN”) Layers with Tunable Refractive Index$

The Journal of Physical Chemistry C, 2018

This article describes novel composite thin films consisting of GaN, C, and Ga (termed "GaCN", as... more This article describes novel composite thin films consisting of GaN, C, and Ga (termed "GaCN", as an analogue to BCN and other carbonitrides) as a prospective material for future optical applications. This is due to their tunable refractive index that depends on the carbon content. The composites are prepared by introducing alternating pulses of trimethylgallium (TMG) and ammonia (NH 3) on silicon substrates to mimic an atomic layer deposition process. Because the GaCN material is hardly reported to the best of our knowledge, a comprehensive characterization is performed to investigate into its chemical nature, primarily to determine whether or not it exists as a single-phase material. It is revealed that GaCN is a composite, consisting of phase-segregated, nanoscale clusters of wurtzitic GaN polycrystals, in addition to inclusions of carbon, nitrogen, and gallium, which are chemically bonded into several forms, but not belonging to the GaN crystals itself. By varying the deposition temperature between 400 and 600°C and the NH 3 partial pressure between 0.7 × 10 −3 and 7.25 mbar, layers with a wide compositional range of Ga, C, and N are prepared. The role of carbon on the GaCN optical properties is significant: an increase of the refractive index from 2.19 at 1500 nm (for carbon-free polycrystalline GaN) to 2.46 (for GaCN) is achieved by merely 10 at. % of carbon addition. The presence of sp 2hybridized CN clusters and carbon at the interface of the GaN polycrystals are proposed to determine their optical properties. Furthermore, the formation of the GaN polycrystals in the composite occurs through a TMG:NH 3 surface-adduct assisted pathway, whereas the inclusions of carbon, nitrogen, and gallium are formed by the thermal decomposition of the chemisorbed TMG species.

Journal of Applied Physics, 2018

Optics Express, 2017

This paper presents a low power monolithically integrated optical transmitter with avalanche mode... more This paper presents a low power monolithically integrated optical transmitter with avalanche mode light emitting diodes in a 140 nm silicon-on-insulator CMOS technology. Avalanche mode LEDs in silicon exhibit wide-spectrum electroluminescence (400 nm < λ < 850 nm), which has a significant overlap with the responsivity of silicon photodiodes. This enables monolithic CMOS integration of optocouplers, for e.g. smart power applications requiring high data rate communication with a large galvanic isolation. To ensure a certain minimum number of photons per data pulse (or per bit), light emitting diode drivers must be robust against process, operating conditions and temperature variations of the light emitting diode. Combined with the avalanche mode light emitting diode's steep current-voltage curve at relatively high breakdown voltages, this conventionally results in high power consumption and significant heating. The presented transmitter circuit is intrinsically robust against these issues, thereby enabling low power operation.

Optics Express

Research

Although it is well known that plants emit acoustic pulses under drought stress, the exact origin... more Although it is well known that plants emit acoustic pulses under drought stress, the exact origin of the waveform of these ultrasound pulses has remained elusive. Here we present evidence for a correlation between the characteristics of the waveform of these pulses and the dimensions of xylem vessels in plants. Using a model that relates the resonant vibrations of a vessel to its dimension and viscoelasticity, we extract the xylem radii from the waveforms of ultrasound pulses and show that these are correlated and in good agreement with optical microscopy. We demonstrate the versatility of the method by applying it to shoots of ten different vascular plant species. In particular, for Hydrangea quercifolia, we further extract vessel element lengths with our model and compare them with scanning electron cryo-microscopy. The ultrasonic, non-invasive characterization of internal vessel dimensions enables a breakthrough in speed and accuracy in plant phenotyping and stress-detection.

IEEE Electron Device Letters

2020 IEEE SENSORS, 2020

Fifth Conference on Sensors, MEMS, and Electro-Optic Systems, 2019

2017 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD), 2017

IEEE Transactions on Electron Devices, 2018

IEEE Journal of the Electron Devices Society, 2018

$Research paper thumbnail of Composite GaN–C–Ga (“GaCN”) Layers with Tunable Refractive Index$

The Journal of Physical Chemistry C, 2018

Journal of Applied Physics, 2018

Optics Express, 2017