C/L-band emission of InAs QDs monolithically grown on Ge substrate

In recent years, the growing demand for silicon based light sources has boosted the research field of III-V/IV hybrid lasers. Here, the C/L-band light emission (1.53 μm-1.63 μm) of InAs/In0.25Ga0.75As quantum dots (QDs) epitaxially grown on Ge substrate by solid-source molecular beam epitaxy (MBE) is reported. By hybrid III-V/IV epitaxial growth, ultra-thin and anti-phase domains (APD) free III-V materials are achieved on Ge substrate. Step-graded InGaAs metamorphic buffer layers are applied to reduce the strain in InAs QDs in order to extend the emission wavelength. At last, a high quality InAs/In0.25Ga0.75As QD structure on Ge(001) substrate is obtained, which has a strong C/L-band emission centered at the wavelength of 1.6 μm with a full-width-half-maximum (FWHM) of 57 meV at room temperature.