Transfer doping effects at the organometallic vapor phase epitaxial AlxGa1−xAs-substrate GaAs interface

Abstract
Electron mobilities in Alx Ga1−xAs (0.1≤x≤0.6) crystals grown by organometallic vapor phase epitaxy on semi‐insulating GaAs:Cr have been measured and analyzed. The mobilities are an order of magnitude higher than theoretical predictions, or those obtained in liquid phase epitaxial Alx Ga1−xAs for x≥0.4. The expected lower mobilities are, however, obtained when measurements are made on the epitaxial layer with the substrate removed. A persistent photoconductivity effect is observed at low temperatures in the layers with substrates. The present results indicate that transfer doping is operative at the epilayer‐substrate heterointerface.