Multilayer porous silicon spherical Mie resonator photodiodes with comb-like spectral response in the near infrared region

[EN] Silicon microsphere photodiodes constitute optoelectronic devices able to provide resonance-enhanced photo -current not only in the visible but also in the near infrared range by virtue of their associated Mie resonances. They are synthesized by means of a bottom-up process that allows obtaining thousand of devices in a single batch. The microspheres have revealed an internal structural configuration that strongly influences the photo -current response, thus providing an additional degree of freedom for tuning the properties of the photodiodes. Here, devices with a particular internal configuration consisting of a high porous core, a much less porous surrounding layer and a thin non-porous shell, have been studied. They yield comb like peaked photocurrent spectra that have been fitted to a Mie type model. In addition, net energy conversion at 1500 nm has been demonstrated.