Photoluminescence (PL) and Optically Detected Magnetic Resonance (ODMR) Study of Visible Light Emission from Porous Si

Abstract

ABSTRACTThe photoluminescence (PL) and X-band ODMR of porous Si layers is described and discussed. The layers were prepared by anodizing the (100) face of a Si wafer at 20 mA/cm2 in 20% HF for 5 mai and passively soaking them in 36% HF for up to 10 hrs. The PL was broad and featureless, extending from ˜1.5 to ˜2.1 eV and peaking at 1.68 eV. Its intensity slightly increased upon cooling to 90 K, and then strongly decreased at lower temperatures. A ˜20 G wide asymmetric PL-enhancing ODMR was observed at g ˜2.0031 ±I 0.0009, which could be fit to a sum of two Gaussians. Their g-values were slightly temperature dependent. The ODMR intensity strongly decreased with increasing temperature, and was unobservable above ˜80 K. The results are compared to the optical properties of hydrogenated amorphous Si.