Search results for "Semiconductor device modeling"
showing 7 items of 7 documents
Improved Temperature Coefficient Modeling through the Recombination Parameter $\gamma$
2020
This study presents an injection dependent numerical model relating Shocldey-Read-Hall defect parameters in crystalline silicon with the recombination parameter $\gamma$ . We demonstrate how the model can be used to predict $\gamma$ for various single level defects. Additionally, we show that $\gamma$ can be significantly influenced by the injection level, in contrast to what is commonly assumed. The injection dependence is found to correlate with the temperature sensitivity of the Shocldey-Read-Hall lifetime. Finally, we demonstrate that the model can be used to predict the temperature coefficient of the open circuit voltage without the use of a temperature dependent measurement, enabling …
A summary of expressions for central performance parameters of high efficiency solar cell concepts
2019
This work reviews expressions for central performance parameters of various types of PV-concepts when operating at the radiative limit. Some new expressions not published elsewhere are also included. The performance parameters include the short circuit current density, the open circuit voltage, the maximum power density and the optimal voltage. The cell concepts include single junction cells, cells optically coupled to up- and down-converters, intermediate band solar cells and a couple of implementations of multijunction devices. The Lambert W function is used to express the maximum power density.
Multi-Scale Modeling of Quantum Semiconductor Devices
2006
This review is concerned with three classes of quantum semiconductor equations: Schrodinger models, Wigner models, and fluid-type models. For each of these classes, some phenomena on various time and length scales are presented and the connections between micro-scale and macro-scale models are explained. We discuss Schrodinger-Poisson systems for the simulation of quantum waveguides and illustrate the importance of using open boundary conditions. We present Wigner-based semiconductor models and sketch their mathematical analysis. In particular we discuss the Wigner-Poisson-Focker-Planck system, which is the starting point of deriving subsequently the viscous quantum hydrodynamic model. Furt…
Modeling and parameter identification of crystalline silicon photovoltaic devices
2011
This paper tests the standard single-exponential model of the electrical characteristics of crystalline-Si photovoltaic devices, focusing on the (apparent) shunt current. Measured characteristics of illuminated polycrystalline-Si photovoltaic modules are modeled, and the apparent shunt current is analyzed. It is shown that an Ohmic-like behavior only takes place at voltages well below the maximum-power point. At higher voltages, the apparent shunt current quickly drops to negligible values. Modeling a crystalline-Si PV device with a fixed shunt resistance may therefore lead to underestimation of the maximum power exceeding 10% at certain irradiance levels.
Physically-consistent parameterization in the modeling of solar photovoltaic devices
2011
This research tests the standard one-diode model of a crystalline-Si photovoltaic cell, focusing on the physical accuracy. In particular, the (apparent) shunt resistance and the diode ideality factor are studied. Current-voltage characteristics of illuminated crystalline-Si photovoltaic modules are analyzed, and some limits of applicability of the standard model are given. Typical values of the ideality factor for crystalline-Si devices are derived from own experimental data as well as from recently published literature. It is shown that the contribution of the apparent shunt resistance is only significant for cell voltages below about 0.45 V, and depends on irradiance. This result is consi…
Electric conduction in solids: a pedagogical approach supported by laboratory measurements and computer modelling environments
2008
In this paper we present a pedagogic approach aimed at modeling electric conduction in semiconductors, built by using NetLogo, a programmable modeling environment for building and exploring multi‐agent systems. ‘Virtual experiments’ are implemented to confront predictions of different microscopic models with real measurements of electric properties of matter, such as resistivity. The relations between these electric properties and other physical variables, like temperature, are, then, analyzed.
A Compact SPICE Model for Organic TFTs and Applications to Logic Circuit Design
2016
This work introduces a compact DC model developed for organic thin film transistors (OTFTs) and its SPICE implementation. The model relies on a modified version of the gradual channel approximation that takes into account the contact effects, occurring at nonohmic metal/organic semiconductor junctions, modeling them as reverse biased Schottky diodes. The model also comprises channel length modulation and scalability of drain current with respect to channel length. To show the suitability of the model, we used it to design an inverter and a ring oscillator circuit. Furthermore, an experimental validation of the OTFTs has been done at the level of the single device as well as with a discrete-…