ELECTRIC-FIELD-DEPENDENT ELECTROREFLECTANCE SPECTRA OF VISIBLE-BAND-GAP (INALGA)P QUANTUM-WELL STRUCTURES

We present results from the first studies of electric-field effects on optical transitions in visible-band-gap InGaP/InAlGaP multiple-quantu m-well (MQW) structures. These structures, grown at 775-degrees-C by m etalorganic vapor phase epitaxy on (100) GaAs substrates misoriented 6 -degrees towards [111]A, consist of nominally undoped MQWs surrounded by doped In0.49Al0.51P cladding layers to form p-i-n diodes. The Stark shifts of various allowed and forbidden quantum-well transitions were observed in bias-dependent electroreflectance spectra of In0.49Ga0.51 P/In0.49(Al0.5Ga0.5)0.51P MQW samples with 10-nm-thick layers. We find the magnitude of these shifts to depend on the details of the Mg dopi ng profile, confirming the importance of Mg diffusion and unintentiona l background doping in these materials. Our results show that (InAlGa) P materials are promising for visible-wavelength electro-optic modulat or applications.