MBE growth of highly sensitive silicon PIN diode with magnetic Mn-doped Ge quantum dots for photodetector and solar cell applications.

For the first time, this work reports the fabrication of a p+-i-n + diode with a magnetic Mn-doped Ge quantum embedded in its intrinsic layer for photodetection and photovoltaic applications. The diode with Mn-doped Ge quantum dots is epitaxied by an ultra-high vacuum molecular beam epitaxy (UHV-MBE) reactor on a silicon substrate. Using atomic force microscopy and a superconducting quantum interference device to study the shape and magnetic properties of the Mn-doped Ge QDs revealed that they are uniform, dense, and ferromagnetic. The new p+-i-n + photodiode has a high rectification ratio of > 100 at a bias voltage of Vb = ± 1 V, a high breakdown voltage of 12 V, an ideality factor of n = 1.86, a Schottky barrier height of ϕB = 0.72 eV, and a broad spectral response in the visible with a high photocurrent/dark ratio of about 100. These original results pave the way for the real integration of magnetic Mn-doped Ge quantum dots in advanced optoelectronic and spintronic devices. [ABSTRACT FROM AUTHOR]