SEMI PV31 - Test Method for Spectrally Resolved Reflective and Transmissive Haze of Transparent Conducting Oxide (TCO) Films for PV Application
This Standard was technically approved by the Photovoltaic - Materials Global Technical Committee. This edition was approved for publication by the global Audits and Reviews Subcommittee on December 8, 2016. Available at www.semiviews.org and www.semi.org in March 2017; originally published February 2012.
Transparent conducting oxide (TCO) films used in the photovoltaic industry are textured in order to optimize light absorption and maximize cell efficiency. Frequently, haze measurements are used to characterize such films. The required texture usually is not well defined by a single haze result because the relative amounts of low and high frequency roughness on the surface can both be important. Therefore the haze is frequently determined for a spectrum of source wavelengths. Then the haze values can often be correlated with useful properties of the material.
In the photovoltaic (PV) field, haze is taken as the total integrated reflective or transmissive scatter from the surface of the sample. The basics of this measurement are covered in SEMI MF1048.
This Test Method extends SEMI MF1048 and SEMI PV15 to measurements of reflective and transmissive haze as a function of source wavelength on TCO films used in the PV industry. Reflective haze can be obtained on TCO films deposited on amorphous or other types of silicon. Transmissive haze can be obtained in a similar fashion on TCO films deposited on transparent materials, such as glass.
Haze is determined as a function of the incident wavelength of the source beam. Haze is also determined as a function of the incident angle between the source beam and the film surface normal. If desired, it can also be determined at different positions on the sample film.
Referenced SEMI Standards
SEMI M59 — Terminology for Silicon Technology
SEMI MF1048 — Test Method for Measuring Reflective Total Integrated Scatter
SEMI PV15 — Guide for Defining Conditions for Angle Resolved Light Scatter Measurements to Monitor the Surface Roughness and Texture of PV Materials