Light-induced creation of defects related to low energy photoluminescence in hydrogenated amorphous silicon

Analysis of lifetime distribution of defect luminescence in hydrogenated amorphous silicon

“…The radiative defects in a-Si:H are different from DBs of Si but their nature is still controversial. As we have reported recently [3], the intensity of defect PL in a-Si:H films as grown has been well explained by assuming that the density of radiative defects is proportional to that of dangling bonds. This fact indicates that the radiative defects are also related to threefold coordinated silicon.…”

“…A narrow peak at 1 ms, which is attributed to the emission from triplet excitons, is seen in the PL of 0.95 eV [6]. The broad component is also seen in the lifetime distribution at 0.95 eV indicating that the electron-hole pairs contribute the PL of 0.95 eV [3]. In this study we observed the nature of non-geminate recombination and confirmed the contribution of the electron-hole pairs to the PL of 0.83 and 0.95 eV.…”

“…We required intense defect PL in order to analyze it in detail. We have already reported the dependence of the intensity of the defect PL in a-Si:H films as grown on the spin density [3] which is affected by the substrate temperature T s . In this study, the preparation was done at T s ¼ 150 C in order to obtain the defect PL of the maximum intensity.…”

“…We have also reported light-induced effects on the defect PL in a-Si:H. The increase of the defect PL in intensity after illumination has been studied in details. Such studies yield considerable information of light-induced phenomena in a-Si:H including the spatial distribution of photo-created defects [3].…”

Thermal quenching of defect photoluminescence and recombination rates of electron–hole pairs in a-Si:H

“…The absolute value of τ R0 at T 0 =10-11 K was estimated as follows. We expect η 0 ∼ 0.75 at T = T 0 = 10-11 K for the a-Si:H film of T s = 180°C, from the plot [3] of logI vs. spin density. In our previous studies we have obtained τ 1/2 ∼ 0.52 ms at T = 10-11 K for the case of a-Si:H films as grown at substrate temperature of T s = 200°C [4].…”