Investigation of MOVPE growth of silicon δ-doped GaAs epilayers and InxGa1-xAs/GaAs strained quantum wells

This work presents the investigations of MOVPE growth of silicon delta-doped GaAs epilayers and strained In(x)Gal(1-x)As/GaAs single quantum wells (SQW). The optimal technological parameters for growing well-spatially confined delta-doped layers with high carrier concentrations are estimated and discussed. The electrical and optical properties of the obtained structures were examined using capacitance-voltage measurements (C-P), photoreflectance (PR) and photocurrent (PC) spectroscopy. The work is focused on the investigation of the central Si-b-doped In(x)Gal(1-x)As/GaAs SQW properties. It was found that these structures are more effective in confining carriers than conventional delta-doped epilayers. In addition, placing n-type delta doping into the In(x)Gal(1-x)As quantum well changes significantly its energy band shape (especially a valence band) and causes filling of the lowest subbands of the conduction band. These effects are responsible for changing of the type of possible optical transitions in the QW region, which was confirmed by PC and PR measurements. (C) 2004 Elsevier Ltd. All rights reserved.