Extrinsic ir Photoconductivity of Si Doped with B, Al, Ga, P, As, or Sb

It is shown that silicon doped with B, Al, Ga, P, As, or Sb is a fast, sensitive, and efficient detector of 10.6-μ radiation from a CO2 laser. Experimental results are presented for several moderately compensated specimens. An investigation was made at temperatures from 23°–40°K of the electrical characteristics, time constant, noise, and 10.6-μ photoresponse. The results are interpreted in terms of idealized, non-Ohmic impurity-photoconductor models. Detectivities within a factor of three of ideal background-limited performance were attained, and response times in the nanosecond region were found.