Electrode for energy storage device and method for manufacturing the same

An electrode for an energy storage device comprising:

• a current collector;
• and
• an active material formed over the current collector, the active material including a stack of:
• a crystalline semiconductor film being in contact with the current collector and containing silicon as its main component and also containing germanium;
• and
• a crystalline silicon film being in contact with the crystalline semiconductor film, and having a {110} crystal plane,
• wherein an orientation ratio of the crystalline silicon film on {110} plane is greater than or equal to 20%.

An electrode for an energy storage device comprising:

• a current collector;
• and
• an active material formed over the current collector, the active material including a stack of:
• a crystalline semiconductor film in contact with the current collector, the crystalline semiconductor film including silicon as its main component and a metal element and germanium;
• and
• a crystalline silicon film in contact with the crystalline semiconductor film, the crystalline silicon film including the metal element,
• wherein each of the crystalline semiconductor film and the crystalline semiconductor film has a {110} crystal plane,
• wherein an orientation ratio of the crystalline semiconductor film on {110} plane is greater than or equal to 20%, and
• wherein an orientation ratio of the crystalline silicon film on {110} plane is greater than or equal to 20%.

A method for manufacturing an electrode for an energy storage device comprising the steps of:

• forming an amorphous semiconductor film containing silicon as its main component and also containing germanium over a current collector;
• adding a metal element to the amorphous semiconductor film;
• and
• performing heat treatment on the amorphous semiconductor film after adding the metal element, whereby forming a crystalline semiconductor film;
• wherein the crystalline semiconductor film has a {110} crystal plane, and
• wherein an orientation ratio of the crystalline semiconductor film on {110} plane is greater than or equal to 20%.

A method for manufacturing an electrode for an energy storage device comprising the steps of:

• forming an amorphous semiconductor film containing silicon as its main component and germanium over a current collector;
• forming an amorphous silicon film over the amorphous semiconductor film;
• adding a metal element to the amorphous semiconductor film and the amorphous silicon film;
• performing heat treatment on the amorphous semiconductor film and the amorphous silicon film after adding the metal element to crystallize the amorphous semiconductor film and the amorphous silicon film, whereby forming a crystalline semiconductor film and forming a crystalline silicon film over the crystalline semiconductor film;
• wherein each of the crystalline semiconductor film and the crystalline silicon film has a {110} crystal plane,
• wherein an orientation ratio of the crystalline semiconductor film on {110} plane is greater than or equal to 20%, and
• wherein an orientation ratio of the crystalline silicon film on {110} plane is greater than or equal to 20%.