Light-Generated CurrentECE 2204

Excess Carriers

•Are generated when light is absorbed by the semiconductor because the energy of a photon, if large enough, will break a bond between two atoms in the semiconductor and cause an electron and hole to be formed.▫Examples of devices

Solar Cells Photovoltaics and photoconductors

(photodetectors)

IV Characteristics in the Dark

http://people.seas.harvard.edu/~jones/es154/lectures/lecture_2/diode_characteristics/diode_characteristics.html

+ VD -

ID

IV Characteristic in the Light

http://blog.disorderedmatter.eu/2008/03/05/intermediate-current-voltage-characeristics-of-organic-solar-cells/

Solar Cell Largest area rectangle that can be formed between the x and y axes and the diode’s IV characteristic in Quadrant IV.

The position of the Maximum Power Point depends on the amount of light absorbed by the solar cell and the temperature of the solar cell in addition to the semiconductor material used to fabricate the diode and the dopant concentrations in the p and n regions.