AlN stressor is proposed to control the operating wavelengths of near-infrared photonic devices of Ge on Si. Ge strips as narrow as 1 μm are epitaxially grown by selective-area chemical vapor deposition on Si, followed by a deposition of a poly-crystalline AlN overlayer by reactive sputtering at a low temperature of 200ºC. The AlN layer successfully induces a tensile strain to narrow the bandgap, as observed in the Raman and photoluminescence spectra. The piezoelectric effect of AlN is potentially applicable to an electrical tuning of the spectral absorption of Ge.