Photoluminescence study of type-II InGaPN/GaAs quantum wells.
Nearly lattice-matched In(0.528)Ga(0.472)P(1-y)Ny bulk layer and In(0.528)Ga(0.472)P(1-y)Ny/GaAs and GaAs/ In(0.528)Ga(0.472)P(1-y)Ny quantum wells with higher N content, y = 0.027, were grown on GaAs(001) substrates by metalorganic vapor phase epitaxy. High-resolution X-ray diffraction results demonstrated the high quality of both the layer and quantum wells with fairly flat interfaces. Temperature dependent photoluminescence results showed that a near-band-edge emission is dominant in the bulk In(0.528)Ga(0.472)P(0.973)N(0.027) layer, which at low temperature (T < 100 K) is associated with localized emissions centered at approximately 1.73 eV. Bandgap of In(0.528)Ga(0.472)P(0.973)N(0.027) was examined to be 1.81 and 1.78 eV at 10 K and room-temperature, respectively. Low temperature (10 K)-photoluminescence spectrum obtained from the GaAs/InxGa(1-x)P(1-y)Ny quantum well also exhibited red emission at 1.73 eV attributed to the emission from the InGaPN barrier. In addition, there are the extra weak peaks appear in a near-infrared energy range at 1.357 and 1.351 eV for InxGa(1-x)P(1-y)Ny/GaAs and GaAs/InxGa(1-x)P(1-y)Ny quantum wells, respectively. Such optical transitions are considered as an indirect transition between electrons located in the InGaPN and holes located in the GaAs regions. This situation suggested that both the In(0.528)Ga(0.472)P(0.973)N(0.027)/GaAs and GaAs/In(0.528)Ga(0.472)P(0.973)N(0.027) quantum wells exhibits a type-II quantum structure. This interpretation is justified when the valence and conduction band offsets of the type-II band alignment, which are relatively approximated to be 450 and 160 meV, are properly taken into account.
Department of Physics, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
Dares
D
Kaewket
Sakuntam
S
Sanorpim
Sukkaneste
S
Tungasmita
Ryuji
R
Katayama
Kentaro
K
Onabe