Rapid progress has been made on GaN based power devices with breakdown voltage > 600 V. More recently, the vertical power devices have received increasing amount of attention in the community since 1) high quality GaN bulk substrates are readily available commercially, and 2) vertical power devices promise higher power handling capabilities. In this talk, I will present the recent progress made in our group on this topic: from lateral HEMT based SBDs with BV > 1.9 kV to vertical p-n junction based diodes with BV > 3.4 kV, as well as first demonstrations of polarization-doped power devices. I will also show the near unity ideality factor achieved in GaN-on-GaN p-n diodes, which subsequently enabled us to extract SRH nonradiative lifetime in GaN for the first time.