Near-infrared electroluminescence emission from an n-InN nanodots/p-Si heterojunction structure

An n-InN nanodots/p-Si(1 1 1) heterojunction diode was fabricated by plasma-assisted molecular beam epitaxy. The device shows clear rectifying behaviour with a turn-on voltage of approximately 1.2 V at room temperature. The near-infrared electroluminescence (EL) can be observed under forward bias, which covers a wide wavelength range. In comparison with the photoluminescence spectra, the maximum of the EL spectra has a blueshift which is probably due to the size quantization effect of small-sized InN nanodots and their stronger contribution to the EL intensity. On the other hand, there is an obvious enhancement of the less dominant transitions on the short wavelength side of the EL spectra, which may arise from the recombination of the injected holes with the extremely high-density surface electrons of InN nanodots.