Electroluminescence in $n$-GaSb/InAs/$p$-GaSb heterostructures with a single quantum well grown by MOVPE

The electroluminescent characteristics of a type-II $n$-GaSb/$n$-InAs/$p$-GaSb heterostructure with a single deep quantum well grown by metalorganic vapor-phase epitaxy are investigated. The energy-band diagram of the structure and the positions of the electron and heavy-hole energy levels are calculated. The analysis of the current–voltage characteristics demonstrates that the dark current in the structure under study flows via the tunneling mechanism. Intense electroluminescence characterized by a weak temperature dependence was observed in the spectral range of 3–4 $\mu$m at $T$ = 77 and 300 K. The main electroluminescence band ($h\nu$ = 0.40 eV at 77 K) corresponds to direct radiative transitions between electrons from level $E_1$ in the InAs quantum well and heavy holes from the continuum at the $n$-GaSb/$n$-InAs heterointerface. A low-intensity electroluminescence band at $h\nu$ = 0.27 eV ($T$ = 77 K) originates from indirect (tunneling) transitions from the first electron level in the quantum well to the second level of heavy holes localized in the valence-band “notch” at the $n$-InAs/$p$-GaSb heterointerface.