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, both of which increase the optical absorptance of the material. We will discuss the properties of the resulting material, including the presence of an intermediate band, as well as our work on developing laser-processed silicon photodiodes that are sensitive to sub-bandgap wavelengths. Most recently, we have measured the electron lifetime within the doped material, and we have developed methods to control the dopant profile and the material crystallinity. These findings are expected to be useful in designing laser-processed silicon devices.