Multiple junction photovolatic devices and process for making the same

A triple junction photovoltaic device comprising:

• a first photoelectric conversion cell including a first p-type semiconductor layer, a first intrinsic semiconductor layer and a first n-type semiconductor layer in sequential touching contact;
• a second photoelectric conversion cell including a second p-type semiconductor layer, a second intrinsic semiconductor layer and a second n-type semiconductor layer in sequential touching contact;
• and
• a third photoelectric conversion cell including a third p-type semiconductor layer, a third intrinsic semiconductor layer and a third n-type semiconductor layer in sequential touching contact,
• wherein said first cell has a higher band gap energy than said second cell, said second cell has a higher band gap energy than said third cell, said semiconductor layers of said cells are formed of nano-crystalline semiconductors containing silicon as a main constituent.

A method for depositing a nano-crystalline semiconductor layer containing silicon as a principal constituent for a photoelectric conversion cell, the method comprising the steps of:

• supporting a substrate in a reaction chamber;
• introducing a film forming gas into said reaction chamber;
• and
• generating a plasma in said reaction chamber by ionizing said film forming gas for decomposing said film forming gas while simultaneously emitting a laser into said reaction chamber through an incidence window for decomposing said film forming gas, thereby forming a film on said substrate.