Photo-responsive Properties on Locally Confined Ultrathin Silicon Nanowires

We present a concept of hybrid photo-responsive device based on the combination of ultrathin SiNW with quantum dots (QDs). High quality SiNW arrays have been fabricated using a novel top-down process. The SiNW arrays were able to detect light from the UV up to the visible range with good sensitivity, fast response and ultrahigh photo responsivity (R~ 10⁴ A/W) at room temperature. The SiNW arrays have good stabilities over long term measurement as well as a range of experimental conditions (e.g. temperature 273 – 343 K) and even after strong UV radiation exposure (up to 585 J.cm^-2).  The SiNW arrays were coated with cadmium telluride (CdTe) QDs, and the hybrid QD sensitized devices displayed a significant improvement of the photocurrent measured under UV light while preserving their performance under visible light illumination. The sensitivity over a broad illumination range, the stability and high photoresponse of the new hydrid nanostructures is very promising towards the development of novel optoelectronic and photovoltaic devices.