Divacancies in a diode Solid-state defects hold great promise as the building blocks for quantum computers. Most research has focused on defects in diamond, which are difficult to integrate with existing semiconductor technologies. An alternative two-vacancy neutral defect in silicon carbide (SiC) has a long coherence time but suffers from broad optical linewidths and charge instability. Anderson et al. fabricated these defects in a diode made out of commercially available SiC. Reverse voltage created large electric fields within the diode, tuning the frequencies of the defect's transitions by hundreds of gigahertz. The electric fields also caused charge depletion, leading to a dramatic narrowing of the transitions. The technique should be readily generalizable to other quantum defects. Science , this issue p. 1225