New developments in silicon photovoltaic devices

The requirements which silicon photovoltaic devices have to meet in various applications are so widely different that it was necessary to develop three distinct types of devices: (1) A device which is operated in the forward biased condition, useful at moderately low to high light levels, known as a solar cell. (2) A device which is operated in the forward biased condition, useful at very low light levels, known as a low level cell. (3) A device operated in the reverse biased direction at low to high light levels, known as a photodiode. All three types are p-n junction devices, prepared by solid state diffusion methods, with each type designed to yield special characteristics. The spectral response, transient response, and temperature dependence of these devices are considered.