Magneto-photoluminescence in a type-II broken-gap n-GaInAsSb/p-InAs heterojunction

Magneto-photoluminescence in a single type-II broken-gap n-Ga _0.94In_0.06As_0.13Sb_0.87/p-InAs heterostructure with a 2D electron channel at the heterointerface containing two occupied electron subbands has been studied in the spectral range 0.3-0.8 eV in high magnetic fields of up to 10 T at low temperatures (T = 7 K). At photon energies in the range 0.5-0.8 eV, bulk photoluminescence from the layer of the n-GaInAsSb alloy was observed. In the low-energy part of the spectrum (0.3-0.45 eV), three narrow emission bands with photon energies hν _a = 0.419 eV, hν _b = 0.404 eV, and hν _c = 0.384 eV and full widths at half-maximum FWHM = 4-7 meV were observed. These bands are due to radiative transitions of 2D electrons localized in the quantum well on the InAs side near the type-II heterointerface. The electron effective mass in the occupied subband E ₂ was estimated to be m ₂ = 0.027m ₀, which is close to the effective mass at the bottom of the InAs conduction band.