Charge relaxation in a single-electron Si/SiGe double quantum dot

We measure the interdot charge relaxation time T₁ of a single electron trapped in an accumulation mode Si/SiGe double quantum dot. The energy level structure of the charge qubit is determined using photon assisted tunneling, which reveals the presence of a low-lying excited state. We systematically measure T₁ as a function of detuning and interdot tunnel coupling and show that it is tunable over four orders of magnitude, with a maximum of 45 μs for our device configuration.