Electrical Characterization of Semiconductor Diode Using Alternating Signal Measurements at Forward Bias

The general analysis of the forward AC behavior of a semiconductor diode under series mode is pre- sented for the first time.A new method without any particular assumption to characterize a diode was developed. This method can accurately measure the dependence of series resistance, junction capacitance, junction vol- tage, ideality factor, and interfacial layer impedance on forward biases. The measurements confirm that the ne- gative capacitance (NC) of Schottky diode is an effect of the junction, and the interfacial layer can be consi- dered as a layer structure with nonlinear resistance and capacitance.

Gain Switch of an AlGaInP Red Light Semiconductor Laser Diode

We solve the single mode coupled rate equations by computer,simulate the behavior of a gain switch of an AlGaInP red light semiconductor laser diode,and find the characteristic of FWHM of pulses changing with the amplitude of modulation signal, the bias current, and the modulated frequency. On this basis, we conduct experiments. The experiment results accord with the simulations well.

Fabrication of 4H-SiC Merged PN-Schottky Diodes

The design, fabrication and characteristics of 4H SiC merged PN Schottky (MPS) diodes with Ni Schottky contact and junction termination extension (JTE) edge termination are reported. A multiple energy implantation Al in the surface of the n - drift region below the face to face Schottky metal formed pn junctions, which screen the Schottky contact from high electrical, post implantation annealing has been done at 1500℃ for 30min in the ultra high purity Ar ambient. The devices can block more than 600V reverse voltage and the lowest leakage current at -600V is 1×10 -3 A/cm 2, while the forward current density at 3V is more than 200A/cm 2 for 1000μm devices, 1000A/cm 2 at 3 5V for 300μm devices.

Measurement of 3db Bandwidth of Laser Diode Chips

An accurate technique for measuring the frequency response of semiconductor laser diode chips is proposed and experimentally demonstrated.The effects of test jig parasites can be completely removed in the measurement by a new calibration method.In theory,the measuring range of the measurement system is only determined by the measuring range of the instruments network analyzer and photo detector.Diodes' bandwidth of 7 5GHz and 10GHz is measured.The results reveal that the method is feasible and comparing with other method,it is more precise and easier to use.

Growth and Application of Chalcogenides of Lead and Related Compounds

Large grain, low-dislocation, high-quality single crystals of various Pb-salt compounds have been grown reproducibly by the Horizontal Unseeded Vapor Growth (HUVG) technique. The Tunable Diode Lasers with better performance have been made with such crystals. The annealing feature, dislocations and diffusion in the crystals have also been investigated.

Study on Relationship between InGaAsP/InP LPE Wafer Morphology,Interface Property and Device Characteristics

Five kinds of InGaAsP/InP heterostructure materials grown with LPE have been measured by means of Auger electron analysis, X-ray double-crystal diffraction, selective etching and surface morphology analysis. The relation between crystal mismatch and interface property of such materials has been studied and the results could be understood in terms of the growth kinetics at the heterojunction interface. The comparison of the characteristics of the electronic and optoelectronic devices fabricated with the wafers under different interface properties has been carried out. And it also has been demonstrated that the wafer surface morphology changes with the compositional gradation in a certain relationship.

Blue LED as a new treatment to vaginal stenosis due pelvic radiotherapy:Two case reports

BACKGROUND Currently,the advancement cancer treatment technology improves overall survival,however,adverse events are still a challenge for health professional.Genitourinary syndrome of menopause and vaginal stenosis are conditions that impact the quality of life of patients undergoing radiotherapy.We present two such cases in patients with previous cervical and endometrial cancer.These conditions were handled with an innovative method using an energy-based device with blue light emitting diode for concomitant vaginal and vulvar irradiation.Positive impact in clinical findings,cytologic changes,and referred symptoms were documented.CASE SUMMARY One patient diagnosed with vaginal severe vaginal stenosis with previous cervix cancer treatment and other patient diagnosed with mild stenosis with severe dyspareunia and recent endometrium cancer treatment were considered for vulvovaginal treatment with weekly blue led device and closely evaluated with repeated validated questionnaires and cytological samples.CONCLUSION This innovative technique showed an improvement in all areas of the examiner's criteria,the cytological criteria,and most bothered symptoms.

Use of the Scar Acceleration Method/Método de Aceleração Cicatricial—MAC®—in the Treatment of Capsular Contracture: Case Report

Capsular contracture is a frequent complication in the postoperative period of breast implantation. It usually accompanies the appearance of a firm breast that can progress to pain, distortion, and asymmetry of the breasts, requiring surgical revision. The present study is a case report. A 58-year-old woman with a medical diagnosis of capsular contracture of the right breast evidenced by ultrasound. She was referred to the physiotherapy clinic in October 2019 with an initial complaint of pain on palpation, swelling, and stiffness in her right breast. The patient was evaluated and the MACò method was used to treat capsular contracture. For this, 12 sessions of photodynamic therapy were carried out. The treatment included the use of LED by doping: red (300 s), violet (60 s) and blue (120 s), with the use of 1% methylene blue in target areas, three times a week. The patient had the beginning of symptoms’ remission in the fourth visit and total remission in the 12th visit. It was concluded that the use of photodynamic therapy using the MACò method showed improvement in signs and symptoms—the sensation of prosthesis stiffness in the lower and medial region, local temperature, and pain in the right breast. The patient was followed up after treatment and currently, she has no complaints. There was also no need for surgical intervention. In the present case report, the MACò method proved to be effective. Further research is suggested with a cohort of patients with capsular contracture, with randomization and evaluation of a larger number of patients with the referred method.

Effects of the Facet Reflectivity of a Laser Diode on Fiber Bragg Grating Semiconductor Lasers

Effects of facet reflectivity of a laser diode on the performance of fiber Bragg grating semiconductor lasers are studied experimentally. Facet reflectivity of less than 10-4 is necessary to obtain stable oscillation wavelength.

Two-Mode Biomedical Sensor Build-up:Characterization of Optical Amplifier

Intracavity absorption spectroscopy is a strikingly sensitive technique that has been integrated with a two-wavelength setup to develop a sensor for human breath.Various factors are considered in such a scenario,out of which Relative Intensity Noise(RIN)has been exploited as an important parameter to characterize and calibrate the said setup.During the performance of an electrical based assessment arrangement which has been developed in the laboratory as an alternative to the expensive Agilent setup,the optical amplifier plays a pivotal role in its development and operation,along with other components and their significance.Therefore,the investigation and technical analysis of the amplifier in the system has been explored in detail.The algorithm developed for the automatic measurements of the system has been effectively deployed in terms of the laser’s performance.With this in perspective,a frequency dependent calibration has been pursued in depth with this scheme which enhances the sensor’s efficiency in terms of its sensitivity.In this way,our investigation helps us in a better understanding and implementation perspective of the proposed system,as the outcomes of our analysis adds to the precision and accuracy of the entire system.

Stable, efficient diode-pumped femtosecond Yb:KGW laser through optimization of energy density on SESAM

An efficient high-power diode-pumped femtosecond Yb：KGW laser is repored. Through optimization of energy density by semiconductor saturable absorber mirror, output power achieved 2.4 W with pulse duration of 350 fs and repetition rate of 53 MHz at a pump power of 12.5 W, corresponding to an optical-to-optical efficiency of 19.2%. We believe that it is the highest optical-to-optical efficiency for single-diode-numoed bulk Yb：KGW femtosecond lasers to date.

Low threshold voltage light-emitting diode in silicon-based standard CMOS technology

Low-voltage silicon （Si）-based light-emitting diode （LED） is designed based on the former research of LED in Si-based standard complementary metal oxide semiconductor （CMOS） technology. The low-voltage LED is designed under the research of cross-finger structure LEDs and sophisticated structure enhanced LEDs for high efficiency and stable light source of monolithic chip integration. The device size of low-voltage LED is 45.85x38.4 （#m）, threshold voltage is 2.2 V in common condition, and temperature is 27 ~C. The external quantum efficiency is about 10-6 at stable operating state of 5 V and 177 mA.

Characteristics of a GaN-based Gunn diode for THz signal generation

A generalized large-signal computer simulation program for a Gunn oscillator has been developed. The properties of a Gunn diode oscillator based on the widely explored GaN, are investigated using the developed program. The results show some interesting properties in GaN Gunn diodes which are not seen in GaAs and InP diodes. An output power of 1400 kW/cm^2 is achieved from the GaN Gunn diode, as compared to 4.9 kW/cm^2 from a GaAs diode.

Beam steering of external cavity diode laser by an intracavity electro-optic ceramic deflector

A novel beam-steering external cavity diode laser using an intracavity lead lanthanum zirconate titanate （PLZT） electro-optic ceramic deflector is proposed and demonstrated experimentally. The laser consists of a semiconductor laser with single mode fiber coupled output, polarization controller, PLZT electro-optic ceramic deflector, and output concave mirror. By applying proper driven electrical signals on the PLZT electro-optic deflector, the beam deflection angle achieves 5.8 mrad at 1 000 V. A high-speed beam-steering property with less than 120-ns switching time is also observed. Moreover, a good beam quality with

Graded tensile-strained bulk InGaAs/InP superluminescent diode with very wide emission spectrum

A kind of novel broad-band superluminescent diodes (SLDs) using graded tensile-strained bulk InGaAs is developed. The graded tensile-strained bulk InGaAs is obtained by changing only group-Ⅲ trimethyl-gallium source flow during low-pressure metal organic vapor-phase epitaxy. At the injection current of 200 mA, the fabricated SLDs with such structure demonstrate full-width at half-maximum spectral width of 106 nm and the output light power of 13.6 mW, respectively.

Tandem organic light-emitting diodes with buffermodified C_(60)/pentacene as charge generation layer

Buffer-modified C_(60)/pentacene as charge generation layer(CGL) is investigated to achieve effective performance of charge generation. Undoped green electroluminescent tandem organic light-emitting diodes(OLEDs) with multiple identical emissive units and using buffer-modified C_(60)/pentacene organic semiconductor heterojunction(OHJ) as CGL are demonstrated to exhibit better current density and brightness, compared with conventional single-unit devices. The current density and brightness both can be significantly improved with increasing the thickness of Al. However, excessive thickness of Al seriously decreases the transmittance of films and damages the interface. As a result, the maximum current efficiency of 1.43 cd·A^(-1) at 30 mA ·cm^(-2) can be achieved for tandem OLEDs with optimal thickness of Al. These results clearly demonstrate that Cs_2CO_3/Al is an effective buffer for C_(60)/pentacene-based tandem OLEDs.

Parallel optical coherence tomography using a CCD camera

Parallel optical coherence tomography is demonstrated using a 12-bit scientific-grade charge-coupled device array. A superluminescent diode in combination with a free-space Michelson interferometer was employed to achieve 10-μm axial resolution and 1.1-μm transverse resolution on a 902×575 /μm2 field of view. We imaged a test mirror and bovine retinal tissue using a four-step phase shift method.