Contact Diode Research Articles

Self-cooling in reverse biased p-InAsSbP/n-InAs0.9Sb0.1 heterostructures

2D thermal radiation distribution together with I–V and L–I characteristics has been measured and analyzed in forward and reverse biased p–n heterostructures based on InAs0.9Sb0.1 and grown onto n-InAs substrates. The measurements revealed a sufficient difference in the temperature distribution onto the sample surface at forward and reverse bias, which is explained by an impact of heat pump operation initiated by an electron–phonon interaction at the p–n junction and diode contacts at U < 0.

Comparison between contact diode laser with 980 nm and 1470 nm wavelengths for posterior laryngofissure in pigs

To compare two different wavelengths of the surgical contact diode laser (CDL) for producing a posterior laryngofissure in in-vivo pigs. Anesthetized pigs underwent a tracheostomy and an anterior laryngofissure through a cervicotomy. They were randomly selected for the CDL wavelength and Power, according to the peak of Power set at device (980nm wavelength: Ppeak power of 10 W, 15 W, and 20 W, or 1470 nm wavelength: Ppeak 3 W, 5 W, 7 W, 10 W). At the end of the experiment, the laryngotracheal specimen was extracted and sent for histology and morphometry measurements (incision size, depth, area, and lateral thermal damage). Hemodynamic data and arterial blood gases were recorded during the incisions. Statistical analysis of the comparisons between the parameters and groups had a level of significance of p < 0.05. Twenty-six pigs were divided into CDL 980 nm (n = 11) and 1470 nm (n = 15). There was a greater incision area at the thyroid level in the 980 nm CDL and a wider incision at the trachea level, with a larger distance between mucosa borders. There were no significant differences in the area of lateral thermal damage between the two groups and neither difference among the power levels tested. Both wavelengths tested showed similar results in the various combinations of power levels without significant differences in the lateral thermal damage. The posterior laryngofissure incision can be performed by either of the wavelengths at low and medium power levels without great difference on lateral thermal damage.

Endoscopic posterior ventricular cordectomy with contact diode laser: how I do it

BackgroundThe treatment of bilateral vocal fold paralysis is mainly surgical and several procedures can be used to guarantee adequate breathing. Furthermore, other causes of the narrowing of the natural airways could coexist and the treatment should consider all of them.MethodsA supraglottic extension of posterior cordectomy to the false homolateral chord is described, which provides a further widening of the airway while maintaining acceptable voice quality.ConclusionEndoscopic posterior ventricular cordectomy performed by contact diode laser may be a viable and safe option, especially in those patients who present bilateral vocal fold paralysis associated with various degrees of laryngospasm.

Next‐Generation Application‐Based Artificial Intelligence in Modeling and Estimation for Ni/n‐GaAs/In Schottky Barrier Diode

Herein, for Ni/n‐GaAs/In Schottky barrier diode, experimental measurement, modeling, data generation from the model, and parameter estimation processes are simultaneously carried out. In the experimental step, Ni/n‐GaAs/In Schottky barrier diodes are fabricated and annealed from the temperature of 200 °C up to 600 °C with 100 °C steps. Current values are recorded by applying voltage to the diode contacts from −1 V up to 0.5 V. In the modeling step, 1503 experimental current–voltage data are used for 19 different regression models. For Adaptive Neuro Fuzzy System (ANFIS), when root mean square error, mean square error, mean absolute error, and coefficient of determination are calculated 6.0341e‐07, 3.6410e‐13, 2.3873e‐07, and 0.9999 for training, they are obtained 5.8904e‐07, 3.4697e‐13, 2.3083e‐07, and 0.9999 for testing. In the estimation step, the values of electrical parameters are estimated by using Mayfly algorithm. Estimations are performed for all annealing temperatures. In addition, current–voltage data for the annealing temperature of 350 °C are produced by the ANFIS model. Thus, a new‐generation artificial intelligence application, that includes measurement, modeling, and estimation for the Ni/n‐GaAs/In Schottky barrier diode with varying annealing temperatures, is realized and a new perspective is provided to researchers and practitioners.

Thin-Entrance Window Process for Soft X-Ray Sensors

New free electron lasers, such as SLAC’s LCLS-II, will provide unique scientific imaging opportunities. In order to fully utilize these facilities, we need to develop detectors with shallow entrance windows that will enable detection of soft x-rays from 250 eV to 1.5 KeV. Achieving adequately shallow entrance windows is challenging because the high temperature anneal needed to activate the dopant also drives the dopant profile deeper, growing the region that is insensitive to soft x-rays. A new microwave annealing technology provides an efficient way to achieve shallow entrance windows in fully depleted high-resistivity silicon sensors. The microwave anneal technique can activate dopants at low substrate temperature, with minimal dopant diffusion, and can be used to fabricate both n-type and p-type entrance windows. SRP and SIMS measurements were used to verify dopant activation with negligible dopant diffusion. We then applied the microwave anneal process to a planar sensor wafer, using the new process to create the backside diode contact. Electrical test of the resulting sensors shows good reverse bias characteristics. The sensors have been bump-bonded to a read-out ASIC and used successfully to measure an Fe-55 x-ray spectrum. Process and device simulations were performed to characterize the quantum efficiency of the entrance window for soft x-rays. This technique is useful for other sensor applications requiring a shallow entrance window, including detectors for UV photons, low energy ions and low energy electrons.

Heavily Si-doped pulsed sputtering deposited GaN for tunneling junction contacts in UV-A light emitting diodes

We report the characteristics of heavily Si-doped GaN prepared by pulsed sputtering deposition (PSD) and its application as tunneling junction (TJ) contacts for nitride-based light-emitting diodes (LEDs). We determined that the use of PSD allows us to grow extremely heavily Si-doped wurtzite GaN epitaxial layers with [Si] = 1.0 × 1021 cm−3 on commercially available UV-A LED wafers. Then, we processed these samples into LED structures to investigate their device characteristics as TJ-contact LEDs. Compared to commercially available UV-A LEDs with transparent conductive oxide contacts, TJ-contact LEDs with [Si] = 1.0 × 1021 cm−3 at the tunnel-junction interface showed lower differential resistance and, consequently, worked well under a high injection current density of ∼1 kA/cm2 without any degradation. These results indicate that PSD-grown heavily doped n-type GaN is promising for application as a TJ-contact in group III nitride-based optoelectronic devices.

ESD Design and Analysis by Drain Electrode-Embedded Horizontal Schottky Elements for HV nLDMOSs

Electrostatic discharge (ESD) events can severely damage miniature components. Therefore, ESD protection is critical in integrated circuits. In this study, drain-electrode-embedded horizontal Schottky diode contact modulation and Schottky length reduction modulation were performed on a high-voltage 60-V n-channel laterally diffused metal-oxide–semiconductor transistor (nLDMOS) element. The effect of the on-voltage characteristics of cascade Schottky diodes on ESD protection was investigated. By using a transmission-line pulse tester, the trigger voltage, holding voltage, and secondary breakdown current (It2) of the nLDMOS element were determined using the I–V characteristic. As the N+ area was gradually replaced by the parasitic Schottky area at the drain electrode, an equivalent circuit of series Schottky diodes formed, which increased the on-resistance. The larger the Schottky area was the higher the It2 value was. This characteristic can considerably improve the ESD immunity of nLDMOS components (highest improvement of 104%). This is a good strategy for improving ESD reliability without increasing the production steps and fabrication cost.

TRANSSCLERAL DIODE CYCLOPHOTOCOAGULATION IN TREATMENT OF GLAUCOMA.

To assess efficiency and safety of diode cyclophotocoagulation (CPC). Retrospective study included 81 eyes with advanced glaucoma operated with CPC for elevated intraocular pressure (IOP) from January 2017 to January 2019. CPC was performed in retrobulbar anesthesia with contact diode laser FOX (A.R.C. Laser, Germany) of wavelength 810 nm, transsclerally to the ciliary body. Energy settings: intensity 2 W, exposition time 2 s, 18 applications in arc of 360°. Decrease of intraocular pressure was investigated during month 1, 6 and 12 after CPC. Safety was evaluated according to the best corrected visual acuity (BCVA) on Snellen optotypes and number of postoperative complications. Study on 31 eyes of 24 patients, 21 (68 %) women and 10 (32 %) men, with follow-up during more than 12 months. Mean follow-up time was 19.5 ± 6.1 (from 12 to 29) months. Average age was 75.9 ± 9.2 (56 - 93) years. Indication for CPC was primary open angle glaucoma in 15 eyes (49 %), primary angle closure glaucoma in 6 eyes (19 %) and secondary glaucomas in 10 eyes (32 %). All patients were on therapy of 4 antiglaucomatic drops and 10 of them (32 %) on acetazolamide pills. IOP before CPC was 25.4 ± 11.0 (13-56) mm Hg. After 1 year IOP decreased to 16.9 ± 6.1 (8-40) mm Hg. Best corrected visual acuity (BCVA) before CPC was 0.39 ± 0.34 (0-1), 1 year after CPC 0.36 ± 0.33 (0-1). 1 year after CPC, 11 eyes (35 %) lost 0.23 ± 0.14 rows. 6 from these (19 %) due to other acquired ocular pathologies. Hypotony occurred in 6 % and uveitis in 10 % eyes. CPC is asafe and effective method of lowering IOP.

Effect of Different Metallic Contacts on the Device Performance of a p-n Heterostructure of a Topological Insulator and Silicon (p-Bi2Te3/n-Si)

This article investigates the performance of the p-Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Te <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /n-Si heterostructure diode with different metallic contacts. The heterostructure was realized by the thermal coating of a topological insulator (TI) Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Te <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> film on n-Si. The crystal phase study of the Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Te <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> film was done by X-ray diffraction (XRD), while the microstructural and morphological study was done by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The CV characterization for the diode showed almost no hysteresis except for the gold (Au) contact device, which could be due to the trapping of electrons at the interface. The current-voltage (IV) measurement was done in the dark, which confirmed the formation of p-n diode heterostructure. Diode having platinum (Pt) metallic contact exhibited the best ideality factor (n = 7.00), while the diode with gold (Au) contact closely followed it (n = 8.91). The best figure of merit (FOM) ≈ 2.588 was observed for Pt contact device with the maximum rectification ratio (RR) ≈ 442 and majority charge carrier concentration (N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">A</sub> ) = 1.47 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">25</sup> /cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . The experimental results of I - V for different contact devices were further simulated using the two-diode model and various diode parameters were extracted. The current density- voltage (JV) and local ideality factor-voltage (nV) plots were studied to find the ideality factor and recombination current (J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">02</sub> ) for different metallic contact devices. The Pt contact diode was found to be nearest to the ideal behavior of a diode exhibiting the least recombination current (J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">02</sub> ) = 9.7 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-17</sup> A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

Lasers in Tonsillectomy: Revisited With Systematic Review.

In 2005, the National Prospective Tonsillectomy Audit was conducted by the Royal College of Surgeons England, reporting hot tonsillectomy techniques being associated with more postoperative pain and hemorrhage when compared with dissection. In 2006, the National Institute of Clinical Excellence declared its position on laser tonsillectomy reporting that bleeding may be less intraoperatively but is more postoperatively, that initial pain may be less but medium term is more and that healing is delayed. To revisit the literature surrounding laser tonsil surgery and assess the aforementioned factors for any trend changes. A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-style systematic review conducted in July 2019 searched Embase, Medline, and Cochrane databases for randomized controlled trials comparing laser tonsil surgery with other techniques with the terms laser, tonsillectomy, and tonsillotomy for nonmalignant indications. A total of 14 articles were evaluated. A total of 1133 patients received surgery accounting for a total of 2266 tonsil removals. A variety of laser techniques were used including CO2 (66%) potassium-titanyl-phosphate (19%) and contact diode (15%). Nonlaser techniques included dissection (62%), diathermy (20%), and coblation (18%). The summated conclusions suggest that laser techniques are superior regarding intraoperative bleeding and procedure duration. Laser techniques also provide equivocal or superior outcomes regarding postoperative hemorrhage, pain, and total healing time. Outcomes following laser surgery in recent years suggest an overall improvement. This could be due to enhanced familiarity with techniques and established centers performing laser procedures more routinely.

Rational design and fabrication of TiO2 nano heterostructure with multi-junctions for efficient photocatalysis

In addition to the extended light absorption, the effective spatial charge separation is a crucial factor for highly efficient metal-oxide semiconductor-based photocatalysts. Herein, a rational design of metal-semiconductor-metal nano heterostructure for enhancing photocatalytic performance is proposed. The semiconductor nanoparticles are integrated with two metals in one single nano heterostructure. The disordered layers are induced on the surface of TiO2 to promote the light absorption capacity. More importantly, the n-n+ junction is fabricated at the contact region between crystalline TiO2 (n-TiO2) and disordered layers (n+-TiO2). Besides, the Schottky diode and Ohmic contact are formed on n-TiO2 and n+-TiO2, respectively. As a result, the existence of multi-junctions leads to the formation of multiple continuous built-in electric fields, thus remarkably accelerating the spatial separation of charge carriers. The resulting nano heterostructure with multi-junctions (Pt–TiO2–H–Ag) exhibits remarkably promoted photocatalytic performance. The maximum hydrogen generation rate of Pt–TiO2–H–Ag under solar illumination (18001.0 μmol/h/g) is 8.3, 9.3, and 1.5 times superior to that of Pt-loaded P25 (Pt–P25), Pt loaded TiO2 (Pt–TiO2), and hydrogenated Pt–TiO2 (Pt–TiO2–H), respectively. Moreover, the photocatalytic performance under visible illumination is significantly enhanced by Pt–TiO2–H–Ag. Specifically, the H2 generation rate of Pt–TiO2–H–Ag (2382.7 μmol/h/g) is about 15.1, 17.2, and 1.4 times higher than that of Pt–P25, Pt–TiO2, and Pt–TiO2–H, respectively. The corresponding apparent quantum efficiency of Pt–TiO2–H–Ag is 15.8% (420 nm). The nano heterostructure with multi-junctions also exhibits excellent stability after five cycles, remaining hydrogen evolution rates of 15581.5 and 2211.4 μmol/h/g under solar and visible illumination, respectively. This effective and controllable manufacturing strategy could provide new opportunities to simultaneously extend optical absorption and facilitate the spatial charge separation and transport of wide-bandgap metal-oxide semiconductors.

Structural and electrical properties of Pd/p-GaN contacts for GaN-based laser diodes

In this paper, the properties of Pd-based p-contacts on GaN-based laser diodes are discussed. Pd is often the metal of choice for ohmic contacts on p-GaN. However, for Pd/p-GaN ohmic contacts, nanovoids observed at the metal/semiconductor interface can have a negative impact on reliability and also reproducibility. The authors present a thorough analysis of the microstructure of the Pd/p-GaN interface by x-ray photoelectron spectroscopy (XPS) and scanning transmission electron microscopy (STEM). STEM data show that the microvoids at the p-GaN/Pd interface form during rapid thermal annealing. A combination of the following effects is suggested to support the void formation: (1) the differences in thermal expansion coefficients of the materials; (2) excess matrix or impurity atoms in the semiconductor, at the interface, and in the metals, which are released as gases; and (3) the strong antisurfactant effect of Pd on Ga-rich p-GaN surfaces. A slow temperature ramp during contact annealing reduces the formation of voids likely by suppressing the accumulation of gases at the interface. XPS data show that the Ga/N ratio can be reduced by suitable cleaning of the p-GaN surface, which enhances Pd adhesion. As a result, the quality of the contact system is improved by the systematic optimization of the surface cleanliness as well as the annealing parameters, leading to void-free and clean Pd/p-GaN interfaces. The specific contact resistance, extracted from linear transmission line method measurements, is reduced by an order of magnitude to 2 × 10−3 Ω cm² at 1 mA for the same epitaxial layer stack.

Design optimization of semiconductor piezoresistors with Schottky diode contacts

A modeling theory is developed to predict the performance of piezoresistors which incorporate Schottky diode electrical contacts. This new theory allows the design of high performance gauges which can be fabricated using Non-Lithographically-Based Microfabrication (NLBM) techniques. These semiconductor piezoresistors can be designed in customizable sizes and fabricated in parallel in order to integrate position sensing into MEMS flexural positioners. Customizable sensing for nanopositioning platforms will enable advances in a range of nano-scale fabrication and metrology applications. A semiconductor piezoresistor with Schottky diode contacts was fabricated and attached to a titanium flexure. This device is shown to match predicted electrical performance within about 8% and to show a gauge factor of 116, within 2% of the predicted value. Optimized performance limits for Schottky diode semiconductor piezoresistors are identified to be about 127 dB full noise dynamic range for a quarter bridge over a 10 kHz sensor bandwidth on a 600 μm width titanium flexure, making them ideal for sensing on meso-/micro-scale flexural positioners. Methods are suggested for achieving the performance limits indicated above and the impact of these methods on the sensor dynamic range are studied.

Short-Pulse Properties of the Gunn Diode

The pulsed ${I}$ – ${V}$ characteristics of a Gunn diode are measured under the test pulse durations from 18 ns to 50 $\mu \text{s}$ . For the test, a Gunn diode fabricated at the Scientific-Research Institute of Semiconductor Devices (Russia, Tomsk) on an ${n}^{+}$ - ${n}$ - ${n}^{+}$ GaAs epitaxial structure was chosen. We found that it is important to provide low internal resistance of the measurement system to prevent voltage skipping in the suprathreshold section of the ${I}$ – ${V}$ characteristic. The measurement system with an internal resistance of about $0.5~\Omega $ and linear calibration of the measurement circuit has been developed. An increase in the threshold voltage with a decrease in the test pulse duration was observed. This effect is explained by the influence of the contacts’ resistance in combination with the temperature dependence of the active area resistance. It is established that this effect also leads to a delay of the domain mode start. We found that the duration of the test pulse maximally affects the threshold current at the durations approximately equal to the thermal relaxation time of the active area (73 ns). Two components can be singled out in this dependence: the first component is associated with the self-heating of the crystal lattice of active area and the second one (the fastest process, 15 ns) is associated with the transfer of some electrons to the second valley in the hottest part of the active area. Registration of the last process probably can be used for diagnostics of the quality of the Gunn diode contacts.

Wafer-scale mono-crystalline GeSn alloy on Ge by sputtering and solid phase epitaxy

Germanium-tin (GeSn) alloys are of great interest for electronic as well as photonic applications, and their integration on a group-IV (Si or Ge) platform. This letter describes a low deposition temperature, process integration-friendly, high throughput and low cost approach for growing device-quality GeSn epilayers on Ge substrates. Mono-crystalline, wafer-scale GeSn alloy with 3.4% Sn content was grown on Ge (100) substrates by sputtering an amorphous GeSn layer followed by solid phase epitaxy (SPE) at . Deposition of amorphous layers at room temperature enables incorporation of high bulk Sn content in GeSn epilayers. SPE of the amorphous layer at leads to a strained, high quality GeSn epilayer having a low full width half maximum of , root mean square surface roughness of 0.3 nm and a good GeSn/Ge interface as confirmed through extensive x-ray diffraction measurements, atomic force microscopy and transmission electron microscopy imaging. Additionally, an SiO2 capping layer employed during SPE is shown to prevent Sn out-diffusion and segregation at the surface. To examine electrical properties for potential applications of the GeSn/n-Ge heterostructure, metal/GeSn/n-Ge vertical contact diodes and metal/GeSn circular transfer length method contact structures were fabricated and electrically characterized.

Gated Bow-Tie Diode for Microwave to Sub-Terahertz Detection.

We propose a new design microwave radiation sensor based on a selectively doped semiconductor structure of asymmetrical shape (so-called bow-tie diode). The novelty of the design comes down to the gating of the active layer of the diode above different regions of the two-dimensional electron channel. The gate influences the sensing properties of the bow-tie diode depending on the nature of voltage detected across the ungated one as well as on the location of the gate in regard to the diode contacts. When the gate is located by the wide contact, the voltage sensitivity increases ten times as compared to the case of the ungated diode, and the detected voltage holds the same polarity of the thermoelectric electromotive force of hot electrons in an asymmetrically shaped n-n+ junction. Another remarkable effect of the gate placed by the wide contact is weak dependence of the detected voltage on frequency which makes such a microwave diode to be a proper candidate for the detection of electromagnetic radiation in the microwave and sub-terahertz frequency range. When the gate is situated beside the narrow contact, the two orders of sensitivity magnitude increase are valid in the microwaves but the voltage sensitivity is strongly frequency-dependent for higher frequencies.

SnS2/Si vertical heterostructure for high-performance photodetection with large photocurrent and fast speed

It has attracted much research interest for the hot topic of photodetection application based on the two-dimensional (2D) heterostructures, owing to their higher light absorption and large separation efficiency of electron-hole pairs. However, the well-controlled growth with high-production and optoelectronic application of the heterostructures based on 2D materials still face great challenges. Photodetectors fabricated with the 2D SnS2/Si heterostructure have still not been well explored, although Si wafers have been proved to be an important substrate for novel optoelectronic application. Herein, the high-quality SnS2/Si heterostructure with large-size and uniform-thickness was prepared by using of a simple magnetron sputtering and post thermal annealing treatment in S atmosphere. The as-prepared SnS2/Si heterostructure exhibits the robust p-n contact and excellent diode rectification characteristic. The photodetector based on the heterostructure was then fabricated, which presents a reconfigurable switch behavior with a larger photocurrent up to 3.96 mA, a maximum detectivity of ~1011 Jones, a ultrafast response speed of 16 μs, and a broad bandwidth of 11.2 kHz. The highly crystalline and on-stoichiometry SnS2 films become a promising form factor to build the high-performance photodetectors. The SnS2/Si heterostructure devices open up an exciting field for novel optical detection application and optoelectronic memory devices.

Efficient tunnel junction contacts for high-power semipolar III-nitride edge-emitting laser diodes

We demonstrate high-power edge-emitting laser diodes (LDs) with tunnel junction contacts grown by molecular beam epitaxy (MBE). Under pulsed conditions, lower threshold current densities were observed from LDs with MBE-grown tunnel junctions than from similarly fabricated control LDs with ITO contacts. LDs with tunnel junction contacts grown by metal-organic chemical vapor deposition (MOCVD) were additionally demonstrated. These LDs were fabricated using a p-GaN activation scheme utilizing lateral diffusion of hydrogen through the LD ridge sidewalls. Secondary ion mass spectroscopy measurements of the [Si] and [Mg] profiles in the MBE-grown and MOCVD-grown tunnel junctions were conducted to further investigate the results.

Posterior laryngofissure using a surgical contact diode laser: an experimental feasibility study.

To evaluate the feasibility of a 980-nm contact diode laser (CDL) as a method for creating a posterior laryngofissure in live pigs. Twenty-eight Landrace pigs (15-20kg) were anesthetized, intubated, ventilated, and submitted to a cervical tracheostomy. An anterior and posterior midline longitudinal laryngofissure incision was created according to randomization-control (n = 4), posterior laryngofissure with a scalpel blade; electrocautery (n = 12), posterior laryngofissure by electrocautery (10, 15, 20, 25W powers); CDL (n = 12), posterior laryngofissure by the CDL (10, 15, 20, 25W peak powers in pulsed mode). Larynx and proximal trachea were excised, prepared for histopathology, and digital morphometric analysis. Measurements in and within each group were analyzed (Kruskal-Wallis and Dunn test) with a level of significance of p < 0.05. Incision width was not different between the groups, as well as in the powers used in CDL (p = 0.161) and electrocautery group (p = 0.319). The depth of the incisions was smaller in the Laser group compared to control (p = 0.007), and in the electrocautery compared to control (p = 0.026). Incision area was smaller in CDL compared with the control (p = 0.027), and not different between laser and electrocautery groups (p = 0.199). The lateral thermal damage produced by electrocautery was the largest, with a significant difference between laser and electrocautery (p = 0.018), and between electrocautery and control (p = 0.004), whereas the comparison between laser and control showed no significant differences (p = 0.588). The posterior laryngofissure incision using a 980-nm CDL is feasible resulting in smaller incisional area and less lateral thermal damage.

Study of electrical effect of transition-metal dichalcogenide-MoS2 layer on the performance characteristic of Cu2ZnSnS4 based solar cells using wxAMPS

In this study, a numerical investigation of the effects of thickness, carrier and defect density of the copper–zinc–tin–sulphide (CZTS) absorber for a typical CZTS based solar cell and also effects of MoS2 formation between CZTS/Mo was demonstrated for the first time using wxAMPS. We have studied how the output parameters change with absorber and of the (n, p)-type MoS2 and so suggested two different cell structures. By using the baseline structure, an optimum thickness value of 2000 nm was determined for CZTS prior to do carrier and defect density studies. Then the carrier and defect density were found as the same value 1014 cm−3.We have found out that the formation of p-MoS2 interfacial layer in CZTS thin film solar cells induce positive effect. However, the efficiency of the solar cell was decreased with n-MoS2 layer which has detrimental effect on CZTS solar cell by creating an additional back contact diode with p-CZTS and Mo.Consequently, efficiencies around 18.30% were obtained through optimization while that of baseline structure was 12.38%. Our results have shown that the suggested structures both produce higher efficiencies than that of baseline structure and may lead to produce more efficient CZTS-based solar cells.