The direct growth of III-V lasers on the industry-standard Si-platforms is the key for fully integrated Si-photonics. Conventional III-V hetero-epitaxy on Si substrates is plagued by crystalline defects generated at the mismatched interface, and thick buffers are often used to mitigate the issues. Here, we report the direct deposition of room temperature III-V micro- and nano-lasers on amorphous SiO2 layers. Without the requirement of crystalline substrates nor having to cope with the long-lasting lattice-mismatch problem, we demonstrate the direct hetero-epitaxy of dislocation-free III-V nanopillars and micro-islands on amorphous SiO2 layers. As the epitaxial InP crystals are embedded inside a low-index environment, we observed strong room temperature lasing from the as-grown InP crystallites under optical excitation.