The isotypep+hyphen;Ge/phyphen;Al0.85Ga0.15As interface is examined in this study. It is shown that a latticehyphen;matched epitaxial layer ofphyphen;Al0.85Ga0.15onp+hyphen;Ge acts like a minorityhyphen;carrier mirror. Evidence for this action comes from improved shorthyphen;wavelength response of ap+hyphen;nGe solar cell and from a tenfold reduction in the dark saturation current of ap+hyphen;nGe junction. At the same time, thep+hyphen;Ge/phyphen;Al0.85Ga0.15As interface is electrically transparent to majorityhyphen;carrier hole transport. Similarity of measured specific resistivities of Ti/Au ohmic contacts directly to Ge and through aphyphen;Al0.85Ga0.15As layer top+Ge leads to this conclusion in spite of about 1 eV valencehyphen;band offset at the Gehyphen;Al0.85Ga0.15As heterojunction interface. A possible mechanism for the hole transport through such an interface is discussed.
展开▼
