A high gain silicon photodetector

High gain silicon photodetectors were designed and fabricated using a sandwich structure of gold compensated n-type material. Steady-state photoconductive current gains as high as 26 were measured, while transient peak gains of 50 were attained. The measured response time varied from 10 ^-6 to 2×10 ^-7 sec, depending inversely upon the incident light intensity. The electron lifetimes were calculated using the existing capture cross-section data of the gold recombination centers. These results are in good agreement with the estimated electron lifetime based upon the measured photoconductive current gain and the calculated transit time values. The detectivity of some of the devices was typically D ^* (λ p , 900, 1) =9.5×10 ⁹ cm (c/s) ^1/2 /watt and the noise equivalent power NEP = 1.6×10 ^-11 watts/(c/s) ^1/2 .