ECOLOGICAL LIGHT MEASUREMENT IN FORESTS USING THE LIGHT DEGRADATION EFFECT IN HYDROGENATED AMORPHOUS-SILICON (A-SI-H)

A method is presented for ecological light measurements in forests bas ed on the principle that light produces electrically active defects wi thin the mobility gap in semiconductors from hydrogenated amorphous si licon (a-Si:H), causing measurable changes in the photoconductivity of the semiconductor. A comparison with measurements of the relative ill uminance in mixed montane forests led to reasonable results. Suitabili ty for field experiments, drawbacks and possible improvements of this low-cost integrating measurement method, which requires no external en ergy source, are discussed at length.