Abstract

Bright electroluminescence from dopant-free ambipolar lateral p–n junctions in GaAs/AlGaAs single heterointerface heterostructures is used to probe neutral free excitons from two-dimensional electron and hole gases. The electroluminescence spectra reveal a heavy-hole neutral free exciton (X₀) and the high-energy free exciton of the H band (HE). Transition energies, lifetimes, spatial emission profiles, and temperature dependences indicate a predominantly two-dimensional character for these excitons at the single heterointerface. X₀ electroluminescence peaks at 1515.5–1515.7 meV, slightly above the bulk GaAs photoluminescence line at 1515.3 meV, and has a much shorter lifetime than photoluminescence (337 ps versus 1610 ps), consistent with recombination in a confined interfacial layer. HE shows a Stark blueshift under forward bias below threshold, with energies and lifetimes tuned by topgate voltage. The tidal effect in ambipolar field-effect transistors produces an X₀ line at the same energy as in the lateral p–n junction and shows the characteristic nonmonotonic brightness dependence previously seen in quantum-well heterostructures.

Abstract

Bright electroluminescence from dopant-free ambipolar lateral p–n junctions in GaAs/AlGaAs single heterointerface heterostructures is used to probe neutral free excitons from two-dimensional electron and hole gases. The electroluminescence spectra reveal a heavy-hole neutral free exciton (X₀) and the high-energy free exciton of the H band (HE). Transition energies, lifetimes, spatial emission profiles, and temperature dependences indicate a predominantly two-dimensional character for these excitons at the single heterointerface. X₀ electroluminescence peaks at 1515.5–1515.7 meV, slightly above the bulk GaAs photoluminescence line at 1515.3 meV, and has a much shorter lifetime than photoluminescence (337 ps versus 1610 ps), consistent with recombination in a confined interfacial layer. HE shows a Stark blueshift under forward bias below threshold, with energies and lifetimes tuned by topgate voltage. The tidal effect in ambipolar field-effect transistors produces an X₀ line at the same energy as in the lateral p–n junction and shows the characteristic nonmonotonic brightness dependence previously seen in quantum-well heterostructures.

Abstract

Bright electroluminescence from dopant-free ambipolar lateral p–n junctions in GaAs/AlGaAs single heterointerface heterostructures is used to probe neutral free excitons from two-dimensional electron and hole gases. The electroluminescence spectra reveal a heavy-hole neutral free exciton (X₀) and the high-energy free exciton of the H band (HE). Transition energies, lifetimes, spatial emission profiles, and temperature dependences indicate a predominantly two-dimensional character for these excitons at the single heterointerface. X₀ electroluminescence peaks at 1515.5–1515.7 meV, slightly above the bulk GaAs photoluminescence line at 1515.3 meV, and has a much shorter lifetime than photoluminescence (337 ps versus 1610 ps), consistent with recombination in a confined interfacial layer. HE shows a Stark blueshift under forward bias below threshold, with energies and lifetimes tuned by topgate voltage. The tidal effect in ambipolar field-effect transistors produces an X₀ line at the same energy as in the lateral p–n junction and shows the characteristic nonmonotonic brightness dependence previously seen in quantum-well heterostructures.

Abstract

Bright electroluminescence from dopant-free ambipolar lateral p–n junctions in GaAs/AlGaAs single heterointerface heterostructures is used to probe neutral free excitons from two-dimensional electron and hole gases. The electroluminescence spectra reveal a heavy-hole neutral free exciton (X₀) and the high-energy free exciton of the H band (HE). Transition energies, lifetimes, spatial emission profiles, and temperature dependences indicate a predominantly two-dimensional character for these excitons at the single heterointerface. X₀ electroluminescence peaks at 1515.5–1515.7 meV, slightly above the bulk GaAs photoluminescence line at 1515.3 meV, and has a much shorter lifetime than photoluminescence (337 ps versus 1610 ps), consistent with recombination in a confined interfacial layer. HE shows a Stark blueshift under forward bias below threshold, with energies and lifetimes tuned by topgate voltage. The tidal effect in ambipolar field-effect transistors produces an X₀ line at the same energy as in the lateral p–n junction and shows the characteristic nonmonotonic brightness dependence previously seen in quantum-well heterostructures.