  We demonstrate single-electron pumps in dopant-free GaAs 2DEGs with one-gate
pumping, operating in zero magnetic field at temperatures T > 1 K, driven by a
simple RF sine waveform up to 0.85 GHz. An analysis with the decay cascade
model for the first quantized current plateau at 0.5 GHz suggests an error rate
already near one ppm for this first generation of dopant-free pumps.
