Tunnel Release Research Articles

Clinical outcomes analysis of small incision cubital tunnel release

Objective To discuss the clinical application of small incision release for treatment of cubital tunnel syndrome.Methods Twelve cases of cubital tunnel syndrome treated from December 2010 to November 2011 were involved.The preoperative function of the ulnar nerve was evaluated by electromyography.Partial resection of the medial epicondyle and decompression of the ulnar nerve was carried out through a small incision.Postoperative immobilization with a plaster cast lasted for 2 days to protect elbow from excessive movement.Results All of 12 cases were follow-up for 4 months to one year.Markedly improved sensation and extrinsic muscle strength were noted.There was no further atrophy of the intrinsic hand muscles.Claw hand deformities of 6 cases were corrected to some extent.According to the criteria for functional assessment of the upper extremity issued by the Chinese Hand Surgery Society,the results were graded as excellent in 6 cases,good in 4 cases,and fair in 2 cases.The overall rate of excellent and good was 83.3 ％.Conclusion When properly indicated,cubital tunnel syndrome can be treated with small-incision partial resection of the medial epicondyle. Key words: Cubital tunnel syndrome; Ulnar nerve; Claw hand; Small incision

Tunnel-injection GaN quantum dot ultraviolet light-emitting diodes

We demonstrate a GaN quantum dot ultraviolet light-emitting diode that uses tunnel injection of carriers through AlN barriers into the active region. The quantum dot heterostructure is grown by molecular beam epitaxy on AlN templates. The large lattice mismatch between GaN and AlN favors the formation of GaN quantum dots in the Stranski-Krastanov growth mode. Carrier injection by tunneling can mitigate losses incurred in hot-carrier injection in light emitting heterostructures. To achieve tunnel injection, relatively low composition AlGaN is used for n- and p-type layers to simultaneously take advantage of effective band alignment and efficient doping. The small height of the quantum dots results in short-wavelength emission and are simultaneously an effective tool to fight the reduction of oscillator strength from quantum-confined Stark effect due to polarization fields. The strong quantum confinement results in room-temperature electroluminescence peaks at 261 and 340 nm, well above the 365 nm bandgap of bulk GaN. The demonstration opens the doorway to exploit many varied features of quantum dot physics to realize high-efficiency short-wavelength light sources.

Effect of tunneling transfer on thermal redistribution of carriers in hybrid dot-well nanostructures

The thermally induced redistribution of carriers between quantum well (QW) and quantum dot (QD) layers in a hybrid dot-well system composed of InAs QDs and an InGaAs QW is studied by means of photoluminescence (PL) spectroscopy. This redistribution significantly affects the QD and QW PL intensities depending both on the dot-well barrier thickness and height. For comparatively thin barriers, the interplay between tunnel and thermal carrier fluxes becomes crucial, governing the exciton dynamics in a tunnel injection dot-well structure at elevated temperatures. For a sufficiently thick spacer, it is shown that exciton localization within the QW, apparently induced by QD strain fields, has a profound influence on the transfer dynamics at low temperatures.

InGaN/GaN self-organized quantum dot lasers grown by molecular beam epitaxy

Blue-and green-emitting quantum dots have been characterized and ridge waveguide lasers incorporating such quantum dots into the active region have been realized. The laser heteroscturctures were grown by plasma assisted molecular beam epitaxy. Injected carrier lifetimes in the quantum dots have also been measured by temperature dependent and time resolved photoluminescence. A threshold current density of 930A/cm2 in the blue-emitting lasers was measured under pulsed bias. A tunnel injection scheme to inject holes has been incorporated in the design of the green quantum dot lasers, and a threshold current density of 945A/cm2 in the green-emitting lasers has been measured under pulsed bias. Slope efficiencies of 0.41W/A and 0.25W/A have been measured, corresponding to differential quantum efficiencies of 13.9% and 11.3%, in the blue and green lasers, respectively.

Tunnel injection and power efficiency of InGaN/GaN light-emitting diodes

The results of studying the influence of the finite tunneling transparency of injection barriers in light-emitting diodes with InGaN/GaN quantum wells on the dependences of the current, capacitance, and quantum efficiency on the p-n junction voltage and temperature are presented. It is shown that defectassisted hopping tunneling is the main transport mechanism through the space charge region (SCR) and makes it possible to lower the injection barrier. It is shown that, in the case of high hopping conductivity through the injection barrier, the tunnel-injection current into InGaN band-tail states is limited only by carrier diffusion from neutral regions and is characterized by a close-to-unity ideality factor, which provides the highest quantum and power efficiencies. An increase in the hopping conductivity through the space charge region with increasing frequency, forward bias, or temperature has a decisive effect on the capacitance-voltage characteristics and temperature dependences of the high-frequency capacitance and quantum efficiency. An increase in the density of InGaN/GaN band-tail states and in the hopping conductivity of injection barriers is necessary to provide the high-level tunnel injection and close-to-unity power efficiency of high-power light-emitting diodes.

ASSESSING THE VARIABILITY OF INJECTATE DISTRIBUTION FOLLOWING CARPAL TUNNEL INJECTION — A CADAVERIC STUDY

This anatomical study was designed to assess the distribution of a solution (injectate) made up using local anesthetic, steroid and dye into the carpal tunnel using a commonly used injection technique. Dissections were undertaken in 29 embalmed cadaveric wrists. The cadaveric specimens were dissected 24 hours after injection to observe the effect of time on diffusion patterns in both superficial and deep planes. Eighteen of the 29 specimens showed the presence of the injectate in the superficial plane and three preferential patterns of distribution were noted in the deep plane: free in the carpal tunnel, exclusively in the tendon sheath and mixed. This is the first study investigating the delayed diffusion pattern of injectate in the carpal tunnel and illustrates its variability. The findings of variable degree of superficial diffusion and different patterns of intracarpal spread help to offer some explanation regarding the variability of the response following carpal tunnel injection.

Multilevel current stress technique for investigation thin oxide layers of MOS structures

In this study, a new technique of multilevel current stress for investigation thin oxide layers of MOS structures is proposed. This technique allows to investigate the generation and relaxation of positive and negative charges, accumulating in, nano-thickness gate dielectric of MOS structures under many stressing situations. The parameters characterizing the change of charge state in the thin oxide layers of MOS structures during the stress have been monitored by means of time dependence of voltage shift applied to a sample during the injection. The method takes into account the process of the MOS capacitance charging by the constant current pulse. In comparison with the conventional techniques our method is nondestructive and enables to reduce the high-field stress time while measuring the injection current-voltage characteristics of the MOS-structure. We consider this method to provide higher accuracy and to decrease the probability of dielectric breakdown. The application of present technique was carr mied out during the investigation of charge generation and relaxation, during and after high-field tunnel injection of electrons in thin thermal film of SiO2. The thin oxide layers of MOS structures after plasma and irradiation treatments also are investigated.

Band-to-Band Tunneling Injection Insulated-Gate Bipolar Transistor with a Soft Reverse-Recovery Built-In Diode

A band-to-band tunneling injection insulated-gate bipolar transistor (IGBT) featuring a tunnel junction as the collector p-n junction is proposed. The tunnel junction injects not only holes into the n-drift region by diffusion when it is forward biased but also electrons by band-to-band tunneling when it is reverse biased. Thus, the proposed device shows the output characteristics of a reverse conducting IGBT (RC-IGBT). Compared with the conventional RC-IGBT, which is prone to current concentration, the proposed device conducts current uniformly in both forward and reverse conducting states, which are favorable to the increase in conducting capability and the reduction in the reverse recovery peak current. During the reverse recovery, the electrons extracted from the drift region to the collector induce the hole injection into the drift region, which leads to the soft reverse recovery of the built-in diode. In addition, the technological ease of fabrication (no backside photolithography) is another attraction of the proposed device.

Comparing the Effects of Three Different Intravitreal Injection Techniques on Vitreous Reflux and Intraocular Pressure

To compare the effects of straight, oblique, and double-plane tunnel scleral intravitreal injection techniques, on short-term intraocular pressure (IOP) changes, occurrence of vitreous reflux (VR), and/or other complications. A total of 105 patients were included in this prospective study. Patients were assigned randomly to one of the straight injection group (SI; n=35), oblique injection group (OI; n=35), or double-plane tunnel injection group (DPTI; n=35). The occurrence of VR and preinjection and postinjection IOP at 2 and 6 h were compared between groups, and complications were assessed. The mean patient age was 71.1±6.6 years (range 58 to 86 years; 50 women and 55 men). In the SI, OI, and DPTI groups, VR occurred in 18 (51.4%), 12 (34.3%), and 6 patients (17.1%), respectively. Mean preinjection IOPs were 15.4, 14.8, and 15.6 mmHg, and changed to 17.3, 18.0, and 20.0 mmHg at the second hour, and 15.7, 16.2, and 16.1 mmHg at the sixth hour, respectively. No significant differences among the groups were found in terms of complications such as transient mild uveitis or subconjunctival hemorrhage. Double-plane tunnel injection prevents VR from the injection site and has no additional complications than other techniques.

The conductivity of heterostructures based on linear-chain carbon

Results are presented from investigations into the conductivity of heterostructures based on two-dimensionally ordered (TDO) linear-chain carbon (LCC) in the form of Al-LCC-Al and pSi-LCC-Al. The Al-LCC-Al structure is shown to possess a nonlinear ohmic contact with a barrier height of around 0.7 eV. It is shown that an over-barrier (Schottky) mechanism of electron injection to LCC in the forward direction and a tunneling effect (Fowler-Nordheim tunnel injection mechanism) in the backward direction occur in the pSi-LCC-Al heterostructure.

Integration of 1.3-$\mu{\rm m}$ Quantum-Dot Lasers With ${\rm Si}_{3}{\rm N}_{4}$ Waveguides for Single Mode Optical Interconnects

A single mode photonic integrated circuit, consisting of a monolithically integrated quantum-dot laser and a suitably designed <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\rm Si}_{3}{\rm N}_{4}$</tex></formula> waveguide, is demonstrated. The 1.3- <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\mu{\rm m}$</tex></formula> quantum-dot laser incorporates a superlattice barrier, p-doping, and tunnel injection in the active region, demonstrating operation up to 85 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$^{\circ}{\rm C}$</tex></formula> with excellent temperature stability (high <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\rm T}_{0}$</tex></formula> ). The two devices are optimally groove coupled to minimize the losses. Integration of the tapered waveguide with a quantum-dot cross laser is also demonstrated.

GUMBEL DISTRIBUTION AND CURRENT FLUCTUATIONS IN CRITICAL SYSTEMS

We investigate a particular phase transition between two different tunneling regimes, direct and injection (Fowler–Nordheim), experimentally observed in the current–voltage characteristics of the light receptor bacteriorhodopsin (bR). Here, the sharp increase of the current above about 3 V is theoretically interpreted as the cross-over between the direct and injection sequential-tunneling regimes. Theory also predicts a very special behavior for the associated current fluctuations around steady state. We find the remarkable result that in a large range of bias around the transition between the two tunneling regimes, the probability density functions can be traced back to the generalization of the Gumbel distribution. This non-Gaussian distribution is the universal standard to describe fluctuations under extreme conditions.

Electronic structure and optical properties of 1.55 µm emitting InAs/InGaAsP quantum dash tunnel injection structures

Optical spectroscopy studies have been reported on an application-relevant system emitting at 1.55 µm and consisting of an InGaAsP injector quantum well (QW), separated by a thin InP barrier (of various thicknesses) from InAs elongated quantum dots called quantum dashes (QDash). The investigated systems constitute tunnel injection structures, whose operation principle is the transfer of carriers captured by the injector QW to the QDash layer by means of tunnelling. Numerical calculations in the eight-band kp model with a realistic dash geometry are used in order to determine the energies of confined levels and their wave functions, results of which are then verified by comparison with measured photoreflectance spectra and used to interpret spectroscopic findings. The tunnelling of carriers from QW to QDash layer is evidenced by photoluminescence excitation measurements and further supported by unusual temperature behaviour of PL peaks broadenings. Careful numerical analysis of confined states and their wave functions explains optical properties of investigated samples. The suggestions for the proper design of structures based on the injection of carriers for applications in telecom lasers are given; most importantly it is shown that care must be taken so that the QW does not significantly influence the dash emitter.

Effect of localized tail states in InGaN on the efficiency droop in GaN light-emitting diodes with increasing current density

The mechanism of the internal quantum efficiency droop in InGaN/GaN structures with multiple quantum wells at current densities of up to 40 A cm−2 in high-power light-emitting diodes is analyzed. It is shown that there exists a correlation between the efficiency droop and the broadening of the high-energy edge of the emission spectrum with increasing current density. It is also demonstrated that the efficiency is a spectrum-dependent quantity and the emission of higher energy photons starts to decrease at higher current densities. The effect of tunneling and thermally activated mechanisms of thermalization of carriers captured into shallow band-tail states in the energy gap of InGaN on the efficiency and the emission spectrum’s shape is considered. Analysis of the results obtained suggests that the efficiency droop occurs at high current densities because of the relative rise in the contribution from nonradiative recombination via defect states as a result of the increasing occupancy of deep band-tail states in InGaN. It is shown that power efficiency close to the theoretical limit can be obtained in the case of low-voltage tunnel injection into localized band-tail states in the InGaN active region.

Relation between injection barrier and contact resistance in top-contact organic thin-film transistors

We theoretically investigate the carrier injection into top-contact bottom-gate organic thin film transistors. By means of a two-dimensional drift–diffusion model, we explicitly consider thermionic and tunneling injection in combination with subsequent carrier transport into the device. Based on numerical simulations with this model, we determine the contact resistance as a function of the nominal hole injection barrier height and temperature. Depending on the barrier height or the operating temperature, we find three distinct injection regimes. Our work reveals that in all three regimes self-regulating processes exist due to which the influx of current is adjusted according to the needs of the channel at the given point of operation.We explain why the transmission/transfer line method (TLM) for the determination of the contact resistance, Rc, quantitatively fails for non-quasi-ohmic injection. Self-regulation links the contact resistance to the channel resistance and the contact resistance becomes dependent on the channel length. For larger channel lengths, Rc is underestimated by TLM; the method yields overestimated values for small channel devices.

High Temperature Stable Operation of 1.3-$\mu$m Quantum-Dot Laser Integrated With Single-Mode Tapered Si$_{3}$N$_{4}$ Waveguide

A photonic-integrated circuit consisting of a 1.3-μm quantum-dot laser and Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> single-mode tapered waveguide, suitable for high temperature operation, is demonstrated. The laser active region incorporates p-doping, tunnel injection, and a superlattice barrier. The temperature dependence of the threshold current of the discrete laser is characterized by T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ~ ∞ in the temperature range 5 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C ≤ T ≤ 60 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C and 90 K in the range 60 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C <; T ≤ 85 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> C. The Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> tapered waveguide is monolithically integrated with a 2.1-μm coupling groove. The insertion loss of a 160-μm waveguide in the integrated circuit is 2.47 dB.

140. Carpal tunnel injection after failed surgery: A case report

140. Carpal tunnel injection after failed surgery: A case report

Electrical properties of ferroelectric-gate FETs with SrBi2Ta2O9 formed using MOCVD technique

Ferroelectric-gate field-effect transistors (FeFETs) with a Pt/SrBi2Ta2O9/Hf-Al-O/Si gate stack were fabricated using the metal-organic chemical vapor deposition (MOCVD) technique to prepare the SrBi2Ta2O9 (SBT) ferroelectric layer. A good threshold voltage (V th) distribution was found for more than 90 n-channel FeFETs in one chip with a 170 nm SBT layer owing to the good film uniformity of the SBT layer deposited by MOCVD. The average memory window \((V_{\mathrm{w}}^{\mathrm{av}})\) and the standard deviations (σ thl,σ thr) of the left- and right-side branches of the drain-gate voltage curves of the FeFETs yielded a \(V_{\mathrm{w}}^{\mathrm{av}}/(\sigma_{\mathrm{thl}} + \sigma_{\mathrm{thr}})\) value of 5.45, indicating that the FeFETs can be adapted for large-scale-integration. The electric field, the energy band profile in the gate stack, and the gate leakage current were also investigated at high gate voltages. We found that the effect of Fowler–Nordheim tunneling appeared under these conditions. Because of the tunneling injection and trapping of electrons into the gate insulators, the operation voltage ranges of the FeFETs were limited by this tunneling.

Current-voltage characteristics of the double tunnel junctions Co2CrAl–I–Pb/Sn–I–Pb under spin-polarized tunnel injection

Current-voltage characteristics and existence features of a superconducting state under the action of tunneling injection of the spin-polarized current Iinj with a high spin polarization degree (p ≈ 0.97) were studied in double tunneling junctions ferromagnet-insulator-superconductor-insulator-superconductor Co2CrAl–I–Pb/Sn–I–Pb. An empirical formula was proposed for describing a dependence of the energy gap Δ on Iinj. A new spin-polarized inhomogeneous superconducting state consisting of superconducting and resistive regions was found. An existence of the proximity effect through a tunnel barrier between ferromagnetic and superconducting films was established. An effective recombination time of spin-polarized quasiparticles in the nonequilibrium superconductor Pb was estimated.

Physical mechanism of interpoly capacitance reduction in high-voltage stress

Interpoly capacitors show degradation in form of capacitance reduction in the whole range of CV characteristics when subjected to high-bias DC or alternating stress. When using these capacitors in oscillator circuits, shift in the resonant frequency may occur, leading to IC performance failure. Significant capacitor degradation occurs at biases that are much lower than the breakdown voltage BV (already at ∼50% BV), and bellow Qdb limit of interpoly dielectric. Degradation is strongly enhanced with reduction in the interpoly dielectric thickness (ONO or oxinitride). We propose a physical mechanism that completely explains the degradation, which involves electron tunneling injection, trapping in the dielectric and simultaneous poly-depletion of both electrodes. Assuming this model, analytically computed CV curves fully reflect all qualitative features observed in experimental degradation characteristics, and enable quantitative fitting of them. This degradation effect sets reliability limit for decrease in interpoly dielectric thickness in capacitors used in RF ICs, where they are subjected to large voltage excursions.