Band offsets and transitivity ofIn1−xGaxAs/In1−yAlyAs/InP heterostructures

摘要: ${\mathrm{In}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Ga}}_{\mathit{x}}$As/${\mathrm{In}}_{1\mathrm{\ensuremath{-}}\mathit{y}}$${\mathrm{Al}}_{\mathit{y}}$As quantum wells (QW's) and ${\mathrm{In}}_{1\mathrm{\ensuremath{-}}\mathit{y}}$${\mathrm{Al}}_{\mathit{y}}$As layers slightly lattice mismatched to InP substrates are grown by metalorganic chemical-vapor deposition studied calorimetric absorption spectroscopy (CAS), photoluminescence (PL), double-crystal x-ray diffractometry (DXD), Shubnikov--de Haas (SdH) measurements. The layer compositions the strain directly determined from DXD. partly relaxes selection rules forbidden transitions, which more sensitive relative conduction-band discontinuities \ensuremath{\Delta}${\mathit{E}}_{\mathit{c}}$/\ensuremath{\Delta}${\mathit{E}}_{\mathit{g}}$ than allowed ones, appear in CAS spectra of QW's. Comparing energies transitions with detailed band-structure calculations discontinuity is be (72\ifmmode\pm\else\textpm\fi{}4)% for ${\mathrm{In}}_{0.540}$${\mathrm{Ga}}_{0.460}$As/${\mathrm{In}}_{0.531}$${\mathrm{Al}}_{0.469}$As. PL type-II heterostructure ${\mathrm{In}}_{0.489}$${\mathrm{Al}}_{0.511}$As/InP show apart band-gap emissions two spatially indirect across ${\mathrm{In}}_{1\mathrm{\ensuremath{-}}\mathit{y}}$${\mathrm{Al}}_{\mathit{y}}$As/InP interface at 1.240 eV (n=1) 1.271 (n=2). these SdH experiments conjunction self-consistent lattice-matched ${\mathrm{In}}_{0.52}$${\mathrm{Al}}_{0.48}$As \ensuremath{\Delta}${\mathit{E}}_{\mathit{c}}$=252 meV or \ensuremath{\Delta}${\mathit{E}}_{\mathit{c}}$=2.86\ensuremath{\Delta}${\mathit{E}}_{\mathit{g}}$. From results, three ${\mathrm{In}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Ga}}_{\mathit{x}}$As/InP, InP/${\mathrm{In}}_{1\mathrm{\ensuremath{-}}\mathit{y}}$${\mathrm{Al}}_{\mathit{y}}$As, ${\mathrm{In}}_{1\mathrm{\ensuremath{-}}\mathit{y}}$${\mathrm{Al}}_{\mathit{y}}$As/${\mathrm{In}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Ga}}_{\mathit{x}}$As found transitive.