Resonant Tunneling Diode Photodetectors Research Articles

Speed limitations of resonant tunneling diode-based photodetectors.

In this work, we study multiple epitaxial layer structures incorporating a resonant tunneling diode photodetector utilizing the In0.53Ga0.47As/InP material system for operation at the near-infrared region of 1.55 and 1.31 micrometers. We study the photodetection speed of response for these devices and the physical limitations affecting their bandwidth. We show that resonant tunneling diode-based photodetectors have bandwidth limitations due to the charge accumulation near the barriers and report on an operating bandwidth reaching up to 1.75 GHz in particular structures, which is the highest number reported for such detectors to the authors' best knowledge.

Resonant Tunneling Diodes: Mid-Infrared Sensing at Room Temperature.

Resonant tunneling diode photodetectors appear to be promising architectures with a simple design for mid-infrared sensing operations at room temperature. We fabricated resonant tunneling devices with GaInAsSb absorbers that allow operation in the μm range with significant electrical responsivity of 0.97 A/W at 2004 nm to optical readout. This paper characterizes the photosensor response contrasting different operational regimes and offering a comprehensive theoretical analysis of the main physical ingredients that rule the sensor functionalities and affect its performance. We demonstrate how the drift, accumulation, and escape efficiencies of photogenerated carriers influence the electrostatic modulation of the sensor’s electrical response and how they allow controlling the device’s sensing abilities.

Analysis of Excitability in Resonant Tunneling Diode-Photodetectors.

We investigate the dynamic behaviour of resonant tunneling diode-photodetectors (RTD-PDs) in which the excitability can be activated by either electrical noise or optical signals. In both cases, we find the characteristics of the stochastic spiking behavior are not only dependent on the biasing positions but also controlled by the intensity of the input perturbations. Additionally, we explore the ability of RTD-PDs to perform optical signal transmission and neuromorphic spike generation simultaneously. These versatile functions indicate the possibility of making use of RTD-PDs for innovative applications, such as optoelectronic neuromorphic circuits for spike-encoded signaling and data processing.

Optical direct intensity modulation of a 79GHz resonant tunneling diode-photodetector oscillator.

We report on the direct intensity modulation characteristics of a high-speed resonant tunneling diode-photodetector (RTD-PD) with an oscillation frequency of 79 GHz. This work demonstrates both electrical and optical modulation and shows that RTD-PD oscillators can be utilized as versatile optoelectronic/radio interfaces. This is the first demonstration of optical modulation of an RF carrier using integrated RTD-PD oscillators at microwave frequencies.

InAs/GaSb superlattice resonant tunneling diode photodetector with InAs/AlSb double barrier structure

We report on a resonant tunneling diode (RTD) photodetector using type-II InAs/GaSb superlattices with an InAs/AlSb double barrier structure. At 80 K, the maximum response of the detector is at about 4.0 μm and the 50% cutoff wavelength is 4.8 μm. The resonant tunneling mechanism is confirmed by observing the negative differential resistance (NDR) phenomenon. The detector is also tested under illumination by a laser with a wavelength of 3.3 μm. A significant photocurrent and NDR peak shift are observed when changing the laser illumination power. The internal multiplication factor, which means how many excess electrons can be triggered by one absorbed photon, is estimated to be 1.01 × 105 at 4.9 V and is 1.90 × 103 at 1.4 V.

Resonant tunneling diode photodetectors for optical communications

AbstractOptical modulation characteristics of resonant tunneling diode photodetectors (RTD‐PD) are investigated. Intensity modulated light excites the RTD‐PDs to conduct data experiments. Simple and complex data patterns are used with results showing data rates up to 80 and 200 Mbit/s, respectively. This is the first demonstration of complex modulation using resonant tunneling diodes.

P‐Type Doped AlAsSb/GaSb Resonant Tunneling Diode Photodetector for the Mid‐Infrared Spectral Region

AbstractMid‐infrared (MIR) resonant tunneling diode (RTD) photodetectors based on a p‐type doped AlAsSb/GaSb double‐barrier quantum well (DBQW) are proposed and investigated for their optoelectronic transport properties. At room temperature, a distinct resonant tunneling current with a region of negative differential conductance is measured. The peak‐to‐valley current ratio (PVCR) is 1.51. To provide photosensitivity within the MIR spectral region, a lattice‐matched quaternary low‐bandgap GaInAsSb absorption layer with cutoff wavelength of λ = 2.77 μm is integrated near the DBQW. Under illumination with infrared light, photogenerated minority electrons within the absorption layer can drift toward the DBQW, where they accumulate and cause a shift of the current–voltage characteristics toward smaller bias voltages, which can be exploited to measure the incident MIR light power. In a tunable diode laser absorption spectroscopy experiment, the RTD photodetector is used to identify three distinct water absorption lines in the MIR close to λ = 2.61 μm. By adjusting the absorption layer doping concentration, the RTD quantum efficiency can be increased by a factor of 10, resulting in a sensitivity of S = 2.71 A W−1, which corresponds to an estimated multiplication factor of M = 8.6.

Mid-infrared GaSb-based resonant tunneling diode photodetectors for gas sensing applications

We present resonant tunneling diode-photodetectors (RTD-PDs) with GaAs0.15Sb0.85/AlAs0.1Sb0.9 double barrier structures combined with an additional quaternary Ga0.64In0.36As0.33Sb0.67 absorption layer covering the fingerprint absorption lines of various gases in the mid-infrared wavelength spectral region. The absorption layer cut-off wavelength is determined to be 3.5 μm, and the RTD-PDs show peak-to-valley current ratios up to 4.3 with a peak current density of 12 A/cm−2. The incorporation of the quaternary absorption layer enables the RTD-PDs to be sensitive to illumination with light up to the absorption lines of HCl at 3395 nm. At this wavelength, the detector shows a responsivity of 6.3 mA/W. At the absorption lines of CO2 and CO at 2004 nm and 2330 nm, respectively, the RTD-PDs reach responsivities up to 0.97 A/W. Thus, RTD-PDs pave the way towards high sensitive mid-infrared detectors that can be utilized in tunable laser absorption spectroscopy.

Sensitivity of resonant tunneling diode photodetectors

We have studied the sensitivity of AlGaAs/GaAs double barrier resonant tunneling diode photodetectors with an integrated GaInNAs absorption layer for light sensing at the telecommunication wavelength of λ = 1.3 μm for illumination powers from pico- to microwatts. The sensitivity decreases nonlinearly with power. An illumination power increase of seven orders of magnitude leads to a reduction of the photocurrent sensitivity from SI = 5.82 × 103 A W−1 to 3.2 A W−1. We attribute the nonlinear sensitivity–power dependence to an altered local electrostatic potential due to hole-accumulation that on the one hand tunes the tunneling current, but on the other hand affects the lifetime of photogenerated holes. In particular, the lifetime decreases exponentially with increasing hole population. The lifetime reduction results from an enhanced electrical field, a rise of the quasi-Fermi level, and an increased energy splitting within the triangular potential well. The non-constant sensitivity is a direct result of the non-constant lifetime. Based on these findings, we provide an expression that allows us to calculate the sensitivity as a function of illumination power and bias voltage, show a way to model the time-resolved photocurrent, and determine the critical power up to which the resonant tunneling diode photodetector sensitivity can be assumed constant.

共振隧穿二极管近红外探测器的电流抑制方法研究

共振隧穿二极管近红外探测器的电流抑制方法研究

Photocurrent-voltage relation of resonant tunneling diode photodetectors

We have investigated photodetectors based on an AlGaAs/GaAs double barrier structure with a nearby lattice-matched GaInNAs absorption layer. Photons with the telecommunication wavelength λ=1.3 μm lead to hole accumulation close to the double barrier inducing a voltage shift ΔV(V) of the current-voltage curve, which depends strongly on the bias voltage V. A model is proposed describing ΔV(V) and the photocurrent response in excellent agreement with the experimental observations. According to the model, an interplay of the resonant tunneling diode (RTD) quantum efficiency η(V), the lifetime of photogenerated and accumulated charge carriers τ(V), and the RTD current-voltage relation in the dark determines best working parameters of RTD photodetectors. Limitations and voltage dependencies of the photoresponse are discussed.

Resonant tunneling diode photodetector with nonconstant responsivity

Resonant tunneling diode with an In0.53Ga0.47As absorption layer is designed for light detection at 1550nm. The responsivity of the detector is simulated by solving the Tsu–Esaki equation. The simulation results show that the responsivity of the detector is nonconstant. It decreases with the increment of the power density of the incident light. Samples of the detector are fabricated by molecular beam epitaxy. The experimental results show that the responsivity increases while the power density of the incident light decreases which agree with the simulation results. The responsivity reaches 4.8×108A/(W/μm2) at room temperature and 5.0×109A/(W/μm2) at 77K when the power density of the incident light is 1×10−13W/μm2.

Stochastic induced dynamics in neuromorphic optoelectronic oscillators

We investigate the dynamics of optoelectronic oscillator (OEO) systems based on resonant tunneling diode photodetector (RTD-PD) and laser diode hybrid integrated circuits. We demonstrate that RTD-based OEOs can be noise-activated in either monostable or bistable operating conditions, providing a rich variety of signal outputs—spiking, square pulses, bursting—and behaviours—stochastic and coherence resonances—that are similar to that of biological systems such as neurons. The potential for fully monolithic integration of our OEO confers them a great potential in novel neuromorphic optoelectronic circuits for signal processing tasks including re-timing and re-shaping of pulsed signals exploiting either the monostable or the bistable operating conditions.

Excitability and optical pulse generation in semiconductor lasers driven by resonant tunneling diode photo-detectors

We demonstrate, experimentally and theoretically, excitable nanosecond optical pulses in optoelectronic integrated circuits operating at telecommunication wavelengths (1550 nm) comprising a nanoscale double barrier quantum well resonant tunneling diode (RTD) photo-detector driving a laser diode (LD). When perturbed either electrically or optically by an input signal above a certain threshold, the optoelectronic circuit generates short electrical and optical excitable pulses mimicking the spiking behavior of biological neurons. Interestingly, the asymmetric nonlinear characteristic of the RTD-LD allows for two different regimes where one obtain either single pulses or a burst of multiple pulses. The high-speed excitable response capabilities are promising for neurally inspired information applications in photonics.

Photo-Detectors Integrated with Resonant Tunneling Diodes

We report on photo-detectors consisting of an optical waveguide that incorporates a resonant tunneling diode (RTD). Operating at wavelengths around 1.55 μm in the optical communications C band we achieve maximum sensitivities of around 0.29 A/W which is dependent on the bias voltage. This is due to the nature of RTD nonlinear current-voltage characteristic that has a negative differential resistance (NDR) region. The resonant tunneling diode photo-detector (RTD-PD) can be operated in either non-oscillating or oscillating regimes depending on the bias voltage quiescent point. The oscillating regime is apparent when the RTD-PD is biased in the NDR region giving rise to electrical gain and microwave self-sustained oscillations Taking advantage of the RTD's NDR distinctive characteristics, we demonstrate efficient detection of gigahertz (GHz) modulated optical carriers and optical control of a RTD GHz oscillator. RTD-PD based devices can have applications in generation and optical control of GHz low-phase noise oscillators, clock recovery systems, and fiber optic enabled radio frequency communication systems.

Modulation accuracy of binary phase-shift keying signal broadcast after injection locking of a resonant tunneling diode microwave oscillator

Injection of a binary phase-shift keyed signal to a resonant tunneling diode (RTD)-based microwave oscillator is presented in this article. The locked signal is broadcast through a wireless communications link and also converted from optical to radio frequency domain using a RTD photodetector. Modulation accuracy is evaluated through error vector magnitude and bit error rate using computer software routines. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:705–711, 2013; View this article online at wileyonlinelibrary.com. DOI: 10.1002/mop.27403

Delayed Feedback Dynamics of Liénard-Type Resonant Tunneling-Photo-Detector Optoelectronic Oscillators

We use the nonlinear dynamics approach for studying delayed feedback optoelectronic oscillators (OEOs) formed by hybrid integration of resonant tunneling diode (RTD) photo-detectors with laser diodes, in both single and dual optical fiber feedback routes. In the single loop topology, the performance of the RTD-OEO free-running self-sustained oscillator is improved in terms of phase noise, with a compromise between the delay line and the strength of the optical re-injection. In the dual-loop configuration, superior performance is achieved due to the suppression of the side modes associated with the optical cavity length, resulting in a side mode suppression ratio of up to <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${-}{\rm 60}~{\rm dBc}$</tex></formula> of the carrier frequency. We compare experimental results with numerical simulations based on a system of delay differential equations comprising a Liénard oscillator model driven by white Gaussian noise and coupled with laser rate equations. The delayed feedback Liénard oscillator model gives considerable insight into the RTD-OEO dynamical regimes predicting its main features in both single- and dual-loop configurations.