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Minority carrier diffusion length in proton-irradiated indium phosphide using electron-beam-induced current

Hakimzadeh, Roshanak

Abstract Details

1993, Doctor of Philosophy, Case Western Reserve University, Electrical Engineering.
The minority carrier diffusion length (L) is an important parameter in modeling the expected performance of a solar cell. Therefore, an accurate means for its measurement is essential. This work suggests that presently used values of L may be in error by as much as a factor of 3 because of the customary assumption that the edge surface-recombination velocity is infinite. To demonstrate this point, a novel electron-beam induced current (EBIC) technique for determining L was used: a scanning electron microscope (SEM) was used to generate EBIC profiles, and the approach suggested by Watanabe et al. was used to measure the edge surface-recombination velocity (V s) at numerous points along the beam scan. These values were then used in a numerical approximation to a theoretical expression derived by Donolato for the normalized EBIC. This technique was first applied to gallium arsenide (GaAs) p/n concentrator solar cells. It was found that accounting for a finite V s leads to a significant correction to the accepted value of the hole diffusion length (L p) for GaAs. Next the technique was applied to indium phosphide (InP), using gold/p-type InP Schottky barriers, and the electron dif fusion length (In) was measured for the first time taking into account the finite value of V s. For zinc-doped (1 × 1018 cm-3) InP, L n ranged from 0.26 μm to 1.36 μm. Because solar cells used in space are subject to radiation damage from high-energy particles, the reported ability of InP to resist such damage from protons through self-annealing was examined for the case of 2 MeV protons. Although annealing at room temperature was not observed, the diffusion length, L n, did recover with photoinjection and forward-bias injection of minority carriers. In the course of this study, the diffusion length damage coefficient (K L) for 0.5 MeV proton-irradiated InP was measured for the first time.
Wendell Williams (Advisor)
236 p.

Recommended Citations

Citations

  • Hakimzadeh, R. (1993). Minority carrier diffusion length in proton-irradiated indium phosphide using electron-beam-induced current [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1056641481

    APA Style (7th edition)

  • Hakimzadeh, Roshanak. Minority carrier diffusion length in proton-irradiated indium phosphide using electron-beam-induced current. 1993. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1056641481.

    MLA Style (8th edition)

  • Hakimzadeh, Roshanak. "Minority carrier diffusion length in proton-irradiated indium phosphide using electron-beam-induced current." Doctoral dissertation, Case Western Reserve University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=case1056641481

    Chicago Manual of Style (17th edition)