Surface edge states and enhanced emission on topological insulator of silicon oxide

Abstract

The stable form of silicon takes on the structure of diamond (cF8, d-Si) which is an indirect bandgap semiconductor. Its emission efficiency is very lower (about 10−5) that prevents it from being considered as an ext-generation platform for semiconductor technologies [1–5]. Here, we report the formation of a new topological insulator of silicon oxide produced by nanosecond pulsed laser, using a novel two-step preparation methodology, which has a good emission. First, the amorphous silicon layer was fabricated by nanosecond pulsed laser etching and deposition at oxygen environment, then the topological insulator of silicon oxide was prepared by annealing at 1000 °C for suitable time. The stronger emission in visual region was observed in photoluminescence (PL) measurement on the topological insulator doped with lower oxygen density, where its external quantum efficiency in emission rises over 20% by four orders than that on pure silicon. It is interesting that the quantum platform of emission has been founded in the evolution curve of PL intensity with change of excitation power. The physical model shows that the higher emission efficiency is originated from the special electronic properties in the new topological insulator of silicon oxide, which is fundamentally responsible for creating extended edge states. The topological insulator of silicon oxide will become a new potential material for emission on silicon chip.