Laser doping and texturing of silicon for advanced optoelectronic devices

Irradiating a semiconductor sample with intense laser pulses in the presence of dopants drastically changes the optical, material and electronic properties of the sample. The properties of these processed semiconductors make them useful for photodetectors and, potentially, intermediate band solar cells. This talk discusses the processes that lead to doping and surface texturing, which both increase the optical absorption of the material. We will discuss the properties of the resulting material including the formation of an intermediate band. We have developed laser-processed silicon photodiodes that are sensitive to sub-bandgap wavelengths. Recently, we have developed methods to control dopant profile and the material crystallinity, and we have measured the free carrier lifetime within the doped material. These findings are expected to be useful in designing laser-processed silicon devices.