Title :
A simple model of a graded band-gap pn-heterojunction cell
Author_Institution :
Lab. Electron Phys., Helsinki Univ. of Technol., Espoo, Finland
Abstract :
Alloy semiconductors with spatially varying composition represent a very general class of semiconductors having position dependent material parameters. The current-voltage characteristics of a pn-junction is constructed with the aid of drift-diffusion theory. The one dimensional analysis is based on the integration of the differential equations for the quasi-fermi levels. The result is a formally exact, simple equation for the current density, which can be easily used for practical calculations. The treatment introduces a spatial collection efficiency function which gives the probability that a carrier generated at a given point in the cell will contribute to the current. The collection efficiency is closely related to the spectral response function. The results predicted by the model are compared to those obtained from the full numerical simulation
Keywords :
current density; differential equations; diffusion; energy gap; p-n heterojunctions; semiconductor device models; semiconductor materials; solar cells; alloy semiconductors; current density; current-voltage characteristics; differential equations; drift-diffusion theory; graded band-gap pn-heterojunction cell; position dependent material parameters; quasi-fermi levels; spatial collection efficiency function; spatially varying composition; spectral response function; Boundary conditions; Charge carrier density; Current density; Differential equations; Doping; Photonic band gap; Semiconductor process modeling; Spontaneous emission; Surface treatment; Voltage;
Conference_Titel :
Photovoltaic Energy Conversion, 1994., Conference Record of the Twenty Fourth. IEEE Photovoltaic Specialists Conference - 1994, 1994 IEEE First World Conference on
Conference_Location :
Waikoloa, HI
Print_ISBN :
0-7803-1460-3
DOI :
10.1109/WCPEC.1994.520659
