Optical study of the electronic states of In 0.53 Ga 0.47 As/In 0.52 Al 0.48 As quantum wells in high electric fields

摘要: Absorption and electroabsorption spectra of (In,Ga)As/(In,Al)As quantum wells superlattices, grown lattice matched to InP substrates, have been studied compared with model calculations. Heavy-hole excitons dominate the uncoupled wells. They respond very sensitively electric fields, mainly by losing oscillator strength forbidden transitions. The ground state shows pronounced red shift predicted from quantum-confined Stark effect. A substantial increase electron mass energy is observed. This nonparabolicity conduction band can be approximated a linearly increasing mass, i.e., ${\mathit{m}}_{\mathit{e}}$/${\mathit{m}}_{0}$=0.041+0.045E/(1 eV). Superlattices thin barriers develop minibands whose are different those Features arising ${\mathit{M}}_{0}$ ${\mathit{M}}_{1}$ singularities joint density states allow direct measurement width yield conduction-band discontinuity 505\ifmmode\pm\else\textpm\fi{}5 meV. With miniband structure altered gradually. interband transitions moved center at transition energies corresponding heavy- light-hole in