Temperature dependence of the performance of charge-sensitive infrared phototransistors

ArticleinJournal of Applied Physics 105(6):064517 - 064517-8 · April 2009with28 Reads
Impact Factor: 2.18 · DOI: 10.1063/1.3087579 · Source: IEEE Xplore

    Abstract

    The performance of charge-sensitive infrared phototransistors ( λ∼14.7 μ m ) is studied at temperatures of up to 30 K. The devices, with a 16×4 μ m <sup>2</sup> photoactive area, are fabricated in GaAs/AlGaAs double-quantum-well structure. An excellent specific detectivity D<sup>*</sup>=9.6×10<sup>14</sup> cm   Hz <sup>1/2</sup>/ W is derived in a T range of up to T=23 K . Experimental results are theoretically studied based on WKB approximation, in which photogenerated holes in the floating gate (FG) are recombined with thermal emission or thermally assisted tunneling from the outside of FG through the barriers. The model well reproduces the experimental results, including the vanishing of photosignal at 30 K under 280 fW incident radiation. The model is used to predict a temperature-dependent specific detectivity D<sup>*</sup> in ideal devices free from 1/f noise.