The DØ experiment at the Fermilab Tevatron collider currently operates one of the largest silicon detectors in the world. The new DØ inner-layer detector (Layer 0) was installed during the spring 2006 Tevatron shutdown. It features a novel-type, low mass, radiation-hard layer of silicon at a very small radius. The Layer 0 sensors are connected to the readout chips outside the tracking volume via fine-pitched Kapton flex circuit cable (analog cable). The layer 0 is now fully operational and is integrated part of the DØ silicon microstrip tracker (SMT). Preliminary performance of Layer 0 is described.