The keystone to realize a monolithic integrated source on silicon with germanium is to optimize tensile strain and n-doping. In order to realize an integrated compact source, we demonstrate highly strained n-doped germanium microdisks obtained by two approaches using initially compressed silicon nitride (SiN) deposition. In the first approach, the microdisks are fabricated from relaxed Ge. In a second approach, we use tensile-strained Ge grown on a mismatched buffer layer, thus increasing the global strain in the Ge volume and lowering its gradient. A photoluminescence red-shift up to 450 nm is observed, corresponding to more than 1% biaxial strain.