Optical properties of strained-layer InAs/GaAs quantum wells in hetero n-i-p-i structures

Summary form only given. The optical properties of InAs/GaAs layers imbedded in a GaAs doping superlattice are discussed. The low intensity linear transmission of a strained-layer hetero n-i-p-i containing 110 angstrom wide quantum wells is shown. A pronounced dip near 978 nm and a slight depression near 957 nm are attributed to transitions involving excitons in the wells. Nonlinear transmission of the n-i-p-i when illuminated by a HeNe laser is also shown. The laser light excites electron-hole pairs in the structure which partially cancel the built-in electric fields of the p-n junctions, so that the fields across the quantum wells become smaller. The oscillations centered at 978 nm and 957 nm in the resulting nonlinear spectrum are characteristic of blue shifts of the excitonic features. The oscillation centered at 957 nm very clearly shows the presence of an excitonic transition which is barely visible in the linear transmission.