Nanomembrane Quantum‐Light‐Emitting Diodes Integrated onto Piezoelectric Actuators

Abstract

We integrate resonant-cavity light-emitting diodes containing quantum dots onto substrates with giant piezoelectric response. Via strain, the energy of the photons emitted by the diode can be precisely controlled during electrical injection over a spectral range larger than 20 meV. Simultaneously, the exciton fine-structure-splitting and the biexciton binding energy can be tuned to the values required for entangled photon generation.

Strain-inducedg-factor tuning in single InGaAs/GaAs quantum dots

“…In the total range of voltages explored in our experiments (0-500 V), the QD emission lines shift by ∼1 meV. Comparing this result with the one achieved by Trotta et al [17] using very similar devices, and neglecting anisotropic stresses, we estimate a change in strain of the order of −0.025%. This is less than the maximum value achieved by Trotta et al, most likely due to the bonding between the piezo and the nanomembranes which can vary from sample to sample.…”

“…The observed changes in the exciton g factor are significant, however relatively small (in the range of several percent). As the strain-induced shift in the emission energy is at least a factor of 15 smaller than what has been reported in literature for similar devices [12,17], we expect that the observed effect can be greatly enhanced. Using novel devices an even larger tuning range will be possible [28][29][30].…”

“…The QDs are grown by solid source molecular beam epitaxy (MBE) [17]. On a GaAs buffer layer we first deposit a 100-nm-thick Al 0.75 Ga 0.25 As sacrificial layer, followed by a 150-nm-thick layer of intrinsic GaAs.…”

“…Several methods to incorporate strain in a QD layer exist, such as by embedding QDs in a bowed airbridge structure [14] or by integrating the QD layer on piezoelectric material [13,17]. The latter method is applied here.…”

Tuning exciton energy and fine-structure splitting in single InAs quantum dots by applying uniaxial stress

“…8 Therefore, the photon entanglement is destroyed. 3,9 Different tuning techniques to erase the FSS, such as thermal annealing, 10 applying electric fields, [11][12][13] magnetic fields, 14 and strain fields [15][16][17][18][19][20][21][22] have been explored. Recently, a new method of using a microstructured semiconductor-piezoelectric device to build scalable entangled photon sources with self-assembled QDs was proposed, 23,24 and was successfully demonstrated by combined uniaxial stresses along two orthogonal directions, i.e., along [110] and [1-10] crystal axis of GaAs.…”