Ecological light measurement in forests using the light degradation effect in hydrogenated amorphous silicon (a-Si:H)

Abstract

A method is presented for ecological light measurements in forests based on the principle that light produces electrically active defects within the mobility gap in semiconductors from hydrogenated amorphous silicon (a-Si:H), causing measurable changes in the photoconductivity of the semiconductor. A comparison with measurements of the relative illuminance in mixed montane forests led to reasonable results. Suitability for field experiments, drawbacks and possible improvements of this low-cost integrating measurement method, which requires no external energy source, are discussed at length.