Effect of boron compensation on the photovoltaic properties of amorphous silicon solar cells

Intrinsic amorphous silicon films are normally slightly n type. As a result, in n+-i-metal and n+-i-p+ solar cell structures the major potential barrier is at the i-m or i-p+ interfaces. Low levels of boron compensation of the i layer move the Fermi level down to midgap. Further increases in boron render the i layer slightly p type, and move the major barrier to the i-n+ interface. Therefore, it becomes possible to tailor the level of boron doping throughout the i layer so as to achieve high electric fields in all regions of the layer, and thus maximize the short circuit current.