Non-adiabatic single-electron pumps in a dopant-free GaAs/AlGaAs 2DEG

Abstract

We have realized quantized charge pumping using non-adiabatic single-electron pumps in dopant-free GaAs two-dimensional electron gases. The dopant-free III–V platform allows for ambipolar devices, such as p-i-n junctions, that could be combined with such pumps to form electrically driven single photon sources. Our pumps operate at up to 0.95 GHz and achieve remarkable performance considering the relaxed experimental conditions: one-gate pumping in zero magnetic field and temperatures up to 5 K, driven by a simple RF sine waveform. Fitting to a universal decay cascade model yields values for the figure of merit δ that compare favorably to reported modulation-doped GaAs pumps operating under similar conditions. The devices reported here are already suitable for optoelectronics applications, and further improvement could offer a route to a current standard that does not require sub-Kelvin temperatures and high magnetic fields.

Effects of biased and unbiased illuminations on two-dimensional electron gases in dopant-free GaAs/AlGaAs

“…Such devices, with possible applications such as spin-to-photon [36] or photon-to-spin [37] conversions, often need to be periodically warmed up to room temperature to be "reset." This issue is also relevant for some proposed single photon source proposals [38,39] which would use so-called "lateral" dopant-free p-i-n junctions [40][41][42].…”

Formation of a lateral p–n junction light-emitting diode on an n-type high-mobility GaAs/Al0.33Ga0.67As heterostructure

“…We demonstrate controlled, on-demand electroluminescence from the p-n junctions and assign the emission to be from the GaAs quantum well by spectral studies. Starting from n-type GaAs, rather than undoped GaAs as is found in the literature, allows us to simplify the process of fabricating nano-device structures (such as single-electron pumps) on the n-type side by using existing methods, rather than having to devise new methods to do so [17]. Our method is advantageous in that it is compatible with standard nanodevice lithography, enabling easier integration of single-electron sources [18,19] and other device components.…”