Quantum resonant tunneling in semiconductor double-barrier structure (original) (raw)
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Resonant Tunneling in Photonic Double Quantum Well Heterostructures
Nanoscale Research Letters, 2010
Here, we study the resonant photonic states of photonic double quantum well (PDQW) heterostructures composed of two different photonic crystals. The heterostructure is denoted as B/A/B/A/B, where photonic crystals A and B act as photonic wells and barriers, respectively. The resulting band structure causes photons to become confined within the wells, where they occupy discrete quantized states. We have obtained an expression for the transmission coefficient of the PDQW heterostructure using the transfer matrix method and have found that resonant states exist within the photonic wells. These resonant states occur in split pairs, due to a coupling between degenerate states shared by each of the photonic wells. It is observed that when the resonance energy lies at a bound photonic state and the two photonic quantum wells are far away from each other, resonant states appear in the transmission spectrum of the PDQW as single peaks. However, when the wells are brought closer together, coupling between bound photonic states causes an energy-splitting effect, and the transmitted states each have two peaks. Essentially, this means that the system can be switched between single and double transparent states. We have also observed that the total number of resonant states can be controlled by varying the width of the photonic wells, and the quality factor of transmitted peaks can be drastically improved by increasing the thickness of the outer photonic barriers. It is anticipated that the resonant states described here can be used to develop new types of photonicswitching devices, optical filters, and other optoelectronic devices.
Off-center electron transport in resonant tunneling diodes due to incoherent scattering
2003
Multilayered heterostructures are realized by the deposition of different semiconductors with an atomic accuracy of the interfaces. The incorporated potential due to band offsets of the constituent materials is used to build wells and barriers for devices such as resonant tunneling diodes RTDs, quantum well infrared detectors, quantum well lasers, and heterostructure field effect transistors.
1997
Three terminal (31) Double Barrier Resonant Tunneling (DBR1) devices with the base contact to the quantum well have been fabricated from GaAs/AlAs material system. The plane of the very thin quantum well is reached using high selective etching processes and a nonalloyed Ti/Pt/Au metallization scheme is used to obtain a Schottky base contact. DC and AC electrical measurements demonstrate that the base contact lies on the quantum well of the device DBRT structure and the base voltage modulates the collector current. It is shown that the electrical characteristics of these devices enlarge the possibilities of investigation of the DBRT structures and suggest important applications in high-speed electronics.
Physics of resonant tunneling. The one-dimensional double-barrier case
Physical Review B, 1984
In this work we discuss how the occurrence of resonant tunneling through a one-dimensional (1D) double barrier involves some interesting phenomena which have so far been overlooked. The effect of an externally applied electric field is considered, and it is shown that with fully symmetrical barriers it leads to weaker resonances than otherwise possible. Furthermore, the time required for resonance to be fully established is discussed, and it is shown that, depending on the barrier transmission coefficients and experimental conditions, it can be exceedingly long, thus contributing to a reduction of resonance effects on the usual experimental time scale. We alsa show that resonant tunneling under the usual experimental conditions implies carrier trapping, hence a buildup of space charge available for modifying the potential-energy barrier. Different current behaviors then result from the inherent feedback mechanism. The effects of temperature an the measured current are finally discussed.
Numerical study of coherent tunneling in a double-barrier structure
Thin Solid Films, 1990
We present a transparent and simple theory describing coherent transport of charge carriers through a double-barrier resonant tunnelling structure, including charge build-up in a self-consistent way. Numerical analysis of this model gives I-V characteristics showing negative differential resistance (ndr) and an intrinsic bistability in the ndr region of the curve. We show that it is the charge storage within the quantum well from which the intrinsic bistability results.
Superlattices and Microstructures, 1988
The frequency response of the quantum-well resonant-tunneling diode is calculated usin quantum trans rt theory. The state of the device is represented by & e single-particle F* qner distribution function. The Wi er function is obtained by numerical solution of the Liouville equation, su #? ject to inhomogeneous boundary conditions that represent the ohmic contacts to the device and that introduce dissipation into the model. The small-signal ac response is calculated by a perturbation expansion about the non-equihbnum steady state. The calculatrons indicate that both the negative conductance and nonlinear rectification persist up to the mid terahertz region, for the design studied. This is compared to the lifetime of the resonant state inferred from the width of the scattering resonance.
Optics and Photonics Journal, 2014
In this paper, we theoretically study the quantum size effects on the electronic transmission and current density of the electrons in GaAs/AlGaAs resonant tunneling diodes by solving the coupled equations Schrödinger-Poisson self-consistently. It is found that the resonant peaks of the transmission coefficients shift towards the lower energy regions as the applied bias voltage increases. Our results indicate that the transmission coefficient depends strongly on the variation of the thickness of collector and emitter. We also study the effect of the doping concentration located in the emitter and collector regions on the transmission and current density. We found that the doping concentration can greatly affect the transmission coefficient and the current density; in particular it increases the peak of the current density and displaces the position of the maxima of the current dependence on the applied bias voltage.
Resonant tunneling of electrons in AlSb/GaInAsSb double barrier quantum wells
AIP Advances
We have studied the optical and electronic transport properties of n-type AlSb/GaInAsSb double barrier quantum well resonant tunneling diodes (RTDs). The RTDs were grown by molecular beam epitaxy on GaSb substrates. Collector, quantum well, and emitter regions are comprised of the lattice-matched quaternary semiconductor Ga 0.64 In 0.36 As 0.33 Sb 0.67. Photoluminescence emission spectra reveal a direct bandgap semiconductor with a bandgap energy of Eg ≈ 0.37 eV, which corresponds to a cutoff wavelength of λ ≈ 3.3 μm. The composition-dependent bandgap energy is found to follow Shim's model. At room temperature, we observe resonance current densities of jres = 0.143 kA cm −2 with peak-to-valley current ratios of up to PVCR = 6.2. At cryogenic temperatures T < 50 K, the peak-to-valley current ratio increases up to PVCR = 16.
Superlattices and Microstructures, 1989
The photoluminescence from the well region of a GaAs/AlGaAs double barrier resonant tunneling structure with a 8 nm thick well and 10 nm thick barriers is studied as' a' function of the applied voltage. The width, peak position and integrated area under the photoluminescence peak are all shown to be useful probes of the resonant current. Estimates of the built-in zero-bias potential, the electron density accumulated in the well and the charaoteristic tunneling time are inferred from the data and compared with theory.
We h a ve i n vestigated the in uence of an uniform electric eld, applied in the growth direction, and an uniform magnetic eld, perpendicular to this direction, on the resonant tunneling of electrons in a system formed by t wo asymmetric quantum wells separated by a thin barrier. The semiconductor heterostructure is considered in the e ective mass approximation and one band model. The method we h a ve used to calculated the electronic structure is based on the solution of the time-dependent S c hr odinger equation using the split-operator technique. The tunneling dynamics in the resonance condition is studied using the time evolution of a wave-packet from which w e determine the tunneling time. A comparison with recent experimental data is presented.