Abstract
A theory on the exciton spectra in quantum wells in the presence of an external electric field is presented. The theory emphasizes the usually ignored aspect, namely, that the different exciton spinor components correspond to different in-plane angular momenta and only a single spinor component contributes to the optical transition, which in conjunction with the hybridization of the heavy and light holes will affect the exciton binding energies and oscillator strengths drastically. Numerical calculations based on the theory explain the contradictory behavior of the h12a peak observed by Collins et al., which is actually the 2p state of the light-holeconduction-band (LH1-CB1) exciton.