Light-hole resonant tunnelling through tensile-strained GaInAs quantum wells

We have experimentally investigated the light- and heavy-hole states in tensile-strained GaInAs quantum wells using photoluminescence and photocurrent spectroscopies. Under special conditions, the strain resulting from the lattice mismatch is large enough to reverse the order of the light- and heavy-hole levels (the first light-hole level becomes the ground state). We obtained an experimental light-to-heavy-hole splitting of 50 meV in agreement with calculations. To take advantage of this situation, we realized and characterized the first p-i-p resonant tunnelling diode on an InP substrate. Resonances are clearly visible in the conductance-voltage characteristics but the first resonance is not yet enhanced as expected in this structure. We discuss the reasons that prevent the observation of the first light-hole resonance.