Tunnel Release Research Articles

Correction: Tunnel injection from WS2 quantum dots to InGaN/GaN quantum wells

Correction for ‘Tunnel injection from WS2 quantum dots to InGaN/GaN quantum wells’ by Svette Reina Merden Santiago et al., RSC Adv., 2018, 8, 15399–15404.

Tunnel injection from WS2 quantum dots to InGaN/GaN quantum wells

We propose a tunnel-injection structure, in which WS2 quantum dots (QDs) act as the injector and InGaN/GaN quantum wells (QWs) act as the light emitters. Such a structure with different barrier thicknesses has been characterized using steady-state and time-resolved photoluminescence (PL). A simultaneous enhancement of the PL intensity and PL decay time for the InGaN QW were observed after transfer of charge carriers from the WS2-QD injector to the InGaN-QW emitter. The tunneling time has been extracted from the time-resolved PL, which increases as the barrier thickness is increased. The dependence of the tunneling time on the barrier thickness is in good agreement with the prediction of the semiclassical Wentzel–Kramers–Brillouin model, confirming the mechanism of the tunnel injection between WS2 QDs and InGaN QWs.

Organic color photodetectors based on tri-phase bulk heterojunction with wide sectrum and photoelectronic mltiplication

In order to obtain highly sensitive broadband organic photodetectors (OPDs) used for image sensors with the stable ability to detect three primary colors (RGB), in this paper, the spectral broadening of organic active layer based on tri-phase bulk heterojunction formed by P3HT:PCBM doped with narrow band material PBDT-TT-F which absorbs red light is investigated. The influences of PBDT-TT-F doping ratio on the morphology of active layer film and detector photoelectric properties are further analyzed. Finally, the operating mechanism of trap-assisted photoelectronic multiplication is discussed. On this basis, the detector with 350-750 nm wide spectrum is obtained where the optimum mixing ratio of P3HT:PCBM:PBDT-TT-F is 12:8:3. At a small reverse bias of 1 V, the values of responsivity and external quantum efficiency of the photodetector can reach 470, 381, 450 mA/W and 93%, 89%, 121% respectively under the illumination of three primary colors and its normalized detectivity to the RGB is close to 1012 Jones. Additionally, the maximum relative difference between each parameter and its average value is lower than 20%; the bandwidths are 5, 8, and 8 kHz respectively, which reach the imaging requirements for image sensors. The experimental results show that not only the absorption spectra of the active layer can be broadened but also the carriers collection efficiency of respective electrodes can be well maintained by adding a small quantity of spectral broadening material while keeping the microstructure of the original binary bulk heterojunction. Utilizing the reasonable combination of materials to form electron traps, photoelectronic multiplication can be realized by trap-assisted hole tunneling injection from the Al cathode into active layer, and thus improving the normalized detectivity. Moreover, in order to detect different light intensities, the hole injection barrier width should be controlled by the corresponding light intensity. The resulting OPD shows a good liner response to all three primary colors when light intensity increases from 0.1 to 10 mW/cm2. By adjusting the mixing ratio of the tri-phase materials, the stable ability to detect the primary color can be achieved. The present study paves the way for high responsivity broadband OPDs based on tri-phase bulk heterojunction.

Safety of corticosteroid injection for carpal tunnel syndrome.

IV.

Impact of optical gain broadening on characteristics of response function in the presence and absence of tunnelling injection for quantum dot semiconductor lasers

In this paper, the dynamics of QD semiconductor lasers is investigated numerically. Large and small signal modulations for various inhomogeneous broadenings have been studied. Computationally, we have solved the rate equation for two-state InAs QD semiconductor lasers and the effect of inhomogeneous broadening on response function and output power due to variation of QD parameters have been investigated in the presence and absence of tunnelling. Also, we have studied these effects on optical gain and output power. We have shown that tunnelling injection enhances the efficiency of the semiconductor laser.

Poster 260: Trifid Median Nerve: A Rare Finding During Ultrasound Guided Carpal Tunnel Injection

Poster 260: Trifid Median Nerve: A Rare Finding During Ultrasound Guided Carpal Tunnel Injection

Poster 249: Ultrasound Guided Tarsal Tunnel Injection for Diagnosis and Treatment of Tarsal Tunnel Syndrome: A Case Report

Poster 249: Ultrasound Guided Tarsal Tunnel Injection for Diagnosis and Treatment of Tarsal Tunnel Syndrome: A Case Report

A Sonographically Guided In-Plane Distal-to-Proximal Transligamentous Approach to Carpal Tunnel Injections.

Several sonographically guided injection methods have been described to treat carpal tunnel syndrome. In most cases, the medication diffuses through the carpal tunnel to the site of maximum compression of the nerve after being injected proximally. In this article, we describe a novel method of sonographically guided carpal tunnel injection that utilizes a distal-to-proximal, in-plane, and transligamentous approach. This novel method may provide ergonomic as well as safety advantages to both clinicians and patients, and should be considered by those performing carpal tunnel injections. A distal-to-proximal transligamentous approach is taken, utilizing high-resolution ultrasound guidance. Once the median nerve is sonographically visualized longitudinally within the carpal tunnel, an ulnar shift is made with the transducer. With the median nerve out of view, the needle is inserted in-line and distal to the transducer on the palmar side of the hand, at the ulnar portion of Kaplan's cardinal line. Following a trajectory that is nearly parallel to the median nerve, the needle is sonographically guided to the site of maximum nerve compression. This novel method provides an alternative to previous carpal tunnel injections. The use of ultrasound guidance allows the clinician to visualize and avoid the neurovascular structures near the median nerve and guide the needle to the site of maximum nerve compression. It is possible that this parallel trajectory with the median nerve will provide a lower risk of damage to the nerve.

Anatomic and clinical study of a new surgical procedure with volar single-portal approach for minimally invasive treatment of carpal tunnel syndrome

Objective To investigate the anatomical basis and clinical effects of a new surgical procedure with volar single-portal approach for minimally invasive treatment of carpal tunnel syndrome. Methods On 8 fresh adult upper limb specimens (16 sides), anatomical observation and measurement of carpal tunnel and palm structures were performed to determine the entry point, guide line and operative level of a new surgical procedure with volar single-portal approach for minimally invasive treatment of carpal tunnel syndrome. According to the anatomical findings, the new operation was performed on 68 patients with moderate to severe carpal tunnel syndrome. Postoperative recovery of the patients was followed up and compared with that of 75 patients who received conventional open carpal tunnel release at the corresponding period. Results According to the results of anatomical study, the best entry point of the surgical procedure was determined as following. A line parallel and ulnar to the metacarpophalangeal joint was drawn when the thumb was at maximum radial abduction. Another line was drawn along the long axis between the index and middle fingers. A 1-cm long vertical incision was made at 45° and 1-cm ulnar to the intersection of these two lines. The surgical projection line was the line connecting the surgical incision and the intersection point between palmaris longus tendon and distal wrist crease. The dissection plane was the space between the superficial palmar fascia and the palmar aponeurosis. The 68 minimally invasive surgery treated cases were follow-up for 6 to 12 months, the average follow-up being 9.5 months. Based on the carpal tunnel syndrome postoperative functional assessment criteria proposed by Gu, the results were satisfactory. Postoperative pain symptoms, sensory examination, muscle atrophy, thumb opposition, pinching and grip strength were all significantly improved. There was very little postoperative scar pain. Compared with the conventional surgery the minimally invasive procedure has obvious advantages. Conclusion Volar single-portal approach for minimally invasive treatment of carpal tunnel syndrome has sound anatomical basis. It can effectively reach and divide the transverse carpal ligament, decompress the median nerve. Therefore it is an effective minimally invasive approach in the treatment of carpal tunnel syndrome. Key words: Carpal tunnel syndrome; Surgical procedures, minimally invasive; Anatomy; Clinical study

Electron injection in inverted organic light-emitting diodes with poly(ethyleneimine) electron injection layers

Abstract Electron-injection mechanisms from the air-stable metal-oxide cathode to light-emitting polymer layer are studied. The device configuration is aluminum (Al) doped zinc oxide (AZO)/poly(ethyleneimine) (PEI)/poly(9,9-dioctylfluorene- alt -benzothiadiazole) (F8BT)/molybdenum trioxide/Al, known as an inverted organic light-emitting diode (iOLED). PEI reduces the electron injection barrier between AZO and F8BT by 0.4 eV, and blocks holes at AZO(PEI)/F8BT interface in iOLEDs. The accumulation of holes at the interface greatly enhances the electron injection because of the Fowler-Nordheim type tunneling injection, leading to high current efficiency of iOLEDs.

Electrical and morphological study of carbon nanotubes/polyaniline composite films: A model to explain different tunneling regimes induced by a vertical electric field

The way carbon nanotubes can modify the charge transport of organic materials may open opportunities for new uses. However, the understandings of many intrinsic physical properties associated to those changes are still poor. Here, we report our investigation on the properties of (PAni) and PAni/carbon nanotubes (CNTs) composites obtained by innovative interfacial polymerization method at room temperature. We have used spectroscopic methods (XPS, Raman) and microscopy (SEM) to obtain relevant parameters to combine with our electrical modeling and describe properly the transport characteristics of neat polymer and its composites with carbon nanotubes in different ratios. The devices were prepared in planar field effect transistor (FET) geometry to study the tunneling injection of charge carriers under the influence of the vertical component of a crossed electric field. We found that the tunneling injection is significantly improved using the PAni/CNT composite. This effect is related to morphological changes of the PAni film synthesized in the presence of CNTs, where the PAni polymerization on CNT's surface produces tubular structures covering them. Due to the CNT's high aspect-ratio, there is electric field amplification near to their tips that enhances the tunneling injection from the metallic contacts under the influence of the vertical field. We propose a theoretical model that can predict the electric field intensity of the transition. The number of tube's tips with different amplification factors (β) produces different regimes of tunneling injection in samples with moderate CNT concentration. We then propose a theoretical model that can predict the electric field intensity of the transition between those regimes: essentially it happens when the tunneling current produced by a few junctions with strong β is greater than the current produced by the higher number of junctions with low β. However, as the CNT density increases, the enhancement of the tunneling injection decreases due to electric field screening.

Quantum tunnelling and charge accumulation in organic ferroelectric memory diodes

Non-volatile memories—providing the information storage functionality—are crucial circuit components. Solution-processed organic ferroelectric memory diodes are the non-volatile memory candidate for flexible electronics, as witnessed by the industrial demonstration of a 1 kbit reconfigurable memory fabricated on a plastic foil. Further progress, however, is limited owing to the lack of understanding of the device physics, which is required for the technological implementation of high-density arrays. Here we show that ferroelectric diodes operate as vertical field-effect transistors at the pinch-off. The tunnelling injection and charge accumulation are the fundamental mechanisms governing the device operation. Surprisingly, thermionic emission can be disregarded and the on-state current is not space charge limited. The proposed model explains and unifies a wide range of experiments, provides important design rules for the implementation of organic ferroelectric memory diodes and predicts an ultimate theoretical array density of up to 1012 bit cm−2.

Percutaneous full endoscopic carpal tunnel release using a 5.9 mm endoscope

Objective To apply 5.9 mm whole cervical spine endoscopic system in the minimally invasive carpal tunnel release and evaluate its clinical effects, indications and safety. Methods A total of 11 patients with 14 sides of carpal tunnel syndrome were included in this study. There were 3 males and 8 females, with ages ranging from 36 to 56 years, with an average of 49 years. The right side was involved in 5 cases, left side in 3 cases and bilateral in 3 cases. Using the 5.9 mm endoscope cervical spine minimally invasive surgery system and bipolar radiofrequency, we accomplished percutaneous carpal tunnel release under local anesthesia. Three months after the surgery, Boston Carpal Tunnel Questionnaire (BCTQ), SF-36 and Disability of Arm, Shoulder and Hand (DASH) scores were used to evaluate the results. Results Pain symptoms disappeared entirely in all 11 patients. The nocturnal pain and numbness in 9 patients completely resolved. However, thenar atrophy persisted. The average postoperative DASH score was 13. The average BCTQ symptom severity score was 1.5, while the function grade was 1.5. Postoperative SF-36 scored 40 for the physical part and 57 for the mental part. Nine patients were satisfied with the outcomes, whereas two had a neutral response (neither satisfied nor dissatisfied). There were no postoperative infection, recurrence or neurovascular injuries. Conclusion Percutaneous 5.9 mm full-endoscope technology has advantages such as a smaller incision, a tourniquet-free technique, using local anesthesia, shorter operation time and faster postoperative recovery. These advantages warrant the development of a full endoscopic system dedicated to carpal tunnel release so the minimally invasive treatment of carpal tunnel syndrome will be safer and more effective. Key words: Carpal tunnel syndrome; Endoscopes; Surgical procedures,minimally invasive

Highly Narrowband Photomultiplication Type Organic Photodetectors.

Filterless narrowband response organic photodetectors (OPDs) present a great challenge due to the broad absorption range of organic semiconducting materials. The reported narrowband response OPDs also suffer from low external quantum efficiency (EQE) in the desired response window and low rejection ratio. Here, we report highly narrowband photomultiplication (PM) type OPDs based on P3HT:PC71BM (100:1, wt/wt) as active layer without an optical filter. The full width at half-maximum (fwhm) of the PM-type OPDs can be well retained less than 30 nm under different biases. Meanwhile, the champion EQE and rejection ratio approach 53 500% and 2020 at -60 V bias, respectively. The small fwhm should be attributed to the sharp absorption edge of active layer with small amount of PC71BM. The PM phenomenon is attributed to hole tunneling injection from the external circuit assisted by trapped electron in PC71BM near the Al electrode under light illumination. These highly narrowband PM-type OPDs should have great potential applications in sensitively detecting specific wavelength light and be blind to light outside of the desired response window.

The Accuracy of Common Hand Injections With and Without Ultrasound: An Anatomical Study.

The aim of the study is to determine the accuracy of hand injections with and without the aid of ultrasound (U/S) into the carpal tunnel, thumb carpometacarpal (CMC) joint, first dorsal compartment (DC) and the radiocarpal (RC) joint. Four participants of various level of experience injected the carpal tunnel, thumb CMC, first DC, and RC joint into 40 fresh frozen cadaver specimens with blue dye and radiographic contrast. Participants 1 and 2 were injected without U/S guidance, and participants 3 and 4 were injected with U/S guidance. A successful injection was determined by both fluoroscopy and dissection/direct observation. Additional information was recorded for each injection such as median nerve infiltration and evidence of thumb CMC arthrosis. The overall accuracy for carpal tunnel, thumb CMC, first DC, and RC injections were 95%, 63%, 90%, and 90%, respectively. Success was compared with and without U/S guidance. Success rates were similar for each injection site, except the thumb CMC joint, where U/S participants had 25% higher accuracy. In the setting of thumb CMC arthrosis, the incidence of success was 38% for participants with no U/S aid and 72% for participants with U/S aid. There was a significant difference between participants who used U/S with the participant with more U/S experience being more successful. Carpal tunnel, first DC, and RC injections had an accuracy of greater than 90%. Thumb CMC injections have a lower accuracy (63%) and one can improve accuracy with U/S. The accuracy of U/S-guided injections is dependent on the user and their experience.

Simplified modeling of frequency behavior in photonic crystal vertical cavity surface emitting laser with tunnel injection quantum dot in active region

In this work, the characteristics of the photonic crystal tunneling injection quantum dot vertical cavity surface emitting lasers (PhC-TIQD-VCSEL) are studied through analyzing a modified modulation transfer function. The function is based on the rate equations describing the carrier dynamics at different energy levels of dot and injector well. Although the frequency modulation response component associated with carrier dynamics in wetting layer (WL) and at excited state (ES) levels of dots limits the total bandwidth in conventional QD-VCSEL, our study shows that it can be compensated for by electron tunneling from the injector well into the dot in TIQD structure. Carrier back tunneling time is one of the most important parameters, and by increment of that, the bias current dependence of the total bandwidth will be insignificant. It is proved that at high bias current, the limitation of the WL-ES level plays an important role in reducing the total bandwidth and results in rollovers on 3-dB bandwidth-I curves. In such a way, for smaller air hole diameter of photonic crystal, the effect of this reduction is stronger.

Carrier delocalization in InAs/InGaAlAs/InP quantum-dash-based tunnel injection system for 1.55 µm emission

We have investigated optical properties of hybrid two-dimensional-zero-dimensional (2D-0D) tunnel structures containing strongly elongated InAs/InP(001) quantum dots (called quantum dashes), emitting at 1.55 μm. These quantum dashes (QDashes) are separated by a 2.3 nm-width barrier from an InGaAs quantum well (QW), lattice matched to InP. We have tailored quantum-mechanical coupling between the states confined in QDashes and a QW by changing the QW thickness. By combining modulation spectroscopy and photoluminescence excitation, we have determined the energies of all relevant optical transitions in the system and proven the carrier transfer from the QW to the QDashes, which is the fundamental requirement for the tunnel injection scheme. A transformation between 0D and mixed-type 2D-0D character of an electron and a hole confinement in the ground state of the hybrid system have been probed by time-resolved photoluminescence that revealed considerable changes in PL decay time with the QW width changes. The ...

Ultrasound-guided Cubital Tunnel Injection: Description of Technique and Accuracy in a Cadaver Model

ABSTRACT Introduction: Ulnar nerve (UN) and cubital tunnel morphology is influenced by elbow positioning, potentially compromising injection accuracy and placing the nerve at risk during cubital tunnel injection. Materials and methods: Based on previous anatomical studies of the cubital tunnel, a proof of concept injection model was developed. Eighteen above-elbow cadaver specimens were positioned in 45° elbow flexion and in neutral forearm rotation. The ultrasound transducer was oriented in the transverse plane, in-line with the medial epicondyle and olecranon tip, facilitating visualization of the UN and cubital tunnel. A 25-gauge needle oriented parallel to the ulna was inserted percutaneously at the midpoint between olecranon and epicondyle. The needle was advanced under ultrasound guidance to replicate injection and was secured. Open dissection confirmed its location. Results: 18/18 needle tips were within the cubital tunnel and no needles penetrated the UN. Discussion: Ultrasound-guided cubital tunnel injection, with the elbow in 45° flexion and with neutral forearm rotation was a safe and reliable technique in this cadaveric model. Future clinical studies may evaluate the efficacy of both diagnostic and therapeutic cubital tunnel injection. Nickel BT, Richard MJ, Cotterell I, Crosmer M, Ruch DS, Leversedge FJ. Ultrasound-guided Cubital Tunnel Injection: Description of Technique and Accuracy in a Cadaver Model. The Duke Orthop J 2017;7(1):43-45.

Highly sensitive polymer photodetectors with a wide spectral response range☆☆Project supported by the Fundamental Research Funds for the Central Universities of China (Grant No. 2014JBZ017) and the National Natural Science Foundation of China (Grant Nos. 61377029 and 61675017).

A series of highly sensitive polymer photodetectors (PPDs) was fabricated with P3HT :PBDT-TS1x:PC BM as the active layers, where x represents the PBDT-TS1 doping weight ratio in donors. The response range of PPDs can cover from the UV to near-infrared regions by adjusting the PBDT-TS1 doping weight ratio. The best external quantum efficiency (EQE) values of ternary PPDs with P3HT:PBDT-TS1:PC BM (50:50:1 wt/wt/wt) as the active layers reach 830%, 720%, and 330% under 390-, 625-, and 760-nm light illumination and −10 V bias, respectively. The large EQE values indicate that the photodetectors utilise photomultiplication (PM). The working mechanism of PM-type PPDs can be attributed to interfacial trap-assisted hole tunnelling injection from the external circuit under light illumination. The calculated optical field and photogenerated electron volume density in the active layers can well explain the EQE spectral shape as a function of the PBDT-TS1 doping weight ratio in donors.

Hot electron engineering for boosting electroluminescence efficiencies of silicon-rich nitride light emitting devices

The combination of a SiO2 electron accelerator layer with a silicon-rich nitride layer forming a bilayer embedded in a metal-oxide-semiconductor structure has proved to enhance the integrated visible-infrared EL intensity by more than two orders of magnitude in comparison to the single-layer electroluminescent device approach. The origin of such an improvement is attributed to the massive ionization of defects in the silicon-rich nitride layer by direct impact of injected hot electrons coming from the SiO2 conduction band. Our premises are further corroborated by performing a thorough study of the charge transport in the bilayer structure. This study displays a main electrical mechanism at steady state that combines hot-electron tunneling injection from the SiO2 accelerator layer and space charge-limited current enhanced by Poole-Frenkel conduction from the silicon-rich nitride electroluminescent layer. The proposed electrical mechanism is validated by numerical simulations that provide good agreement with the experimental behavior. These results point out the feasibility of boosting electroluminescence efficiency of Si-based light emitting devices by performing an adequate gate stack engineering that maximizes the hot-electron injection into the electroluminescent layer.