MIS and SIS solar cells

In this review paper we show that MIS (metal-insulator-semiconductor) and SIS (semiconductor-insulator-semiconductor) solar cells are basically one and the same type of device, even though they are usually regarded as being separate and are reported as such. Experimental results on the two most common systems, Al-SiOx-pSi and ITO-SiOx-pSi (ITO designates indium-tin-oxide) are presented to support a model where tunnel current through the insulator or interface is the transport mechanism between the metal or oxide semiconductor (acting as a collecting grid) and the base converting semiconductor. However, the characteristics of the devices are dominated by diffusion current flow in the bulk of the base converting substrate and display the usual Shockley diode equation behavior, in the absence of additional defect current mechanisms.