 1 E F 1  2 E F 2 E vac Metal-metal contact

 1  2 ee ee ee ee E vac Metal-metal contact

          E F  2  1   =

E V E C E F Si   M E F M E vac Metal-silicon contact (smaller metal work function)

E V E C E F Si  E vac ee ee ee ee  Si  M Metal-silicon contact (smaller metal work function)

 M  Si            E F Metal-silicon contact (smaller metal work function)

 M E F M E vac E V E C E F Si  Metal-silicon contact (larger metal work function)

 M E F M E vac E V E C E F Si   ee ee ee ee Metal-silicon contact (larger metal work function)

 Si  M            E F Metal-silicon contact (larger metal work function)

E vac E V E C E F Si  E F M  M Metal-silicon contact (equal work functions)