We report a systematical study of the temperature-dependence of negative deferential resistance (NDR) from double-barrier Al0.35Ga0.65N/GaN resonant tunneling diodes grown by plasma-assisted molecular-beam epitaxy on free-standing GaN substrates. The current–voltage (I–V) characterization was done in the 6–300 K temperature range. A clear NDR signature was observed for mesa sizes of 4 × 4 μm2 a...

Maximum power point trackers (MPPTs) play a vital role in photovoltaic (PV) systems because they increase the eff iciency of the solar photovoltaic system by increasing the power output. MPPT algorithms are necessary because PV arrays have a non linear voltage-current characteristic with a unique point w here the power produced is maximum. The output pow er from the solar panel varies w ith sol...

A study is made of electron tunneling in semiconductor heterostructures having a complex dispersion law. A generalized Fabry–Perot approach is used to describe tunneling across the barrier. Mixing of electron states at the heterojunctions is responsible for the asymmetric resonant structure of the transmission which is characterized by a resonance–antiresonance pair. The resonance corresponds t...

The current-voltage characteristic (IVC) of a system of two small series-connected tunnel junctions is calculated under conditions when the energy spectrum of the central electrode of the system is discrete. The form of the IVC depends substantially on the rate of energy relaxation on this electrode. I t is shown that at typical real values of the system parameters the global IVC singularities ...

The behaviors of the solar cells are decided by the device parameters. Thus, it is necessary to extract these parameters to achieve the optimal working condition. Because the five-parameter model of solar cells has the implicit equation of current-voltage relationship, it is difficult to obtain the parameters with conventional methods. In this work, an optimized method is presented to extract d...

This paper deals with a study of a maximum power point tracking (MPPT) technique based on the Particle Swarm Optimization (PSO) method, which is applied to a single-phase grid-tied photovoltaic system. Since photovoltaic panels have nonlinear voltage-current characteristic curves, when they are submitted to partial shading conditions, it is possible appear distinct local and global maximum powe...

We discuss inherent thermometry in a Superconductor Normal metal Superconductor tunnel junction. In this configuration, the energy selectivity of singleparticle tunneling can provide a significant electron cooling, depending on the bias voltage. The usual approach for measuring the electron temperature consists in using an additional pair of superconducting tunnel junctions as probes. In this p...

A new method for extracting the series resistance and thermal resistance of a Schottky diode is presented. The method avoids the inaccuracies caused by the temperature dependence of the saturation current and ideality factor. These are a major concern for traditional extraction methods, especially when the diode under test has a submicrometer anode diameter and is significantly heated up by the...

We have measured the electrical and optical properties of blue light-emitting diodes ~LEDs! based on III–V nitrides. The current–voltage characteristic is described by means of the relation I5I0 exp(aV). In this equation a is temperature independent, suggesting a process of conduction by tunneling, as was recently reported also for blue-green LEDs based on III–V nitrides @Appl. Phys. Lett. 68, ...