@article{5c39b6ce6d54484dbdd28de0611e743a,
title = "Direct imaging of anisotropic minority-carrier diffusion in ordered GaInP",
abstract = "An all-optical technique has been used to provide the first direct measurement of anisotropic minority-carrier diffusion in an ordered alloy of GaInP. Direct imaging of the minority-carrier diffusion distribution resulting from generation at a quasipoint source is obtained using an optical microscope coupled to a scanning electron microscope. Minority-carrier diffusion lengths ranging from 3 to 60 μm are measured by this technique in double heterostructures of GaInP, GaAs, and GaInAs, providing a key parameter of interest to the performance of state-of-the-art triple junction solar cells. Here we show a direct measurement of anisotropy in minority-carrier mobility in ordered GaInP, which is evident in the oval-shaped distribution of the recombination luminescence. A factor of 1.6 increase in minority electron mobility along the [110] major axis is reported.",
author = "Haegel, {N. M.} and Mills, {T. J.} and M. Talmadge and C. Scandrett and Frenzen, {C. L.} and H. Yoon and Fetzer, {C. M.} and King, {R. R.}",
note = "Funding Information: This work was supported at NPS by NSF Grant Nos. DMR-0203397 and DMR-0526330. Table I. Sample properties and results for minority electron diffusion length and mobility. Sample Band gap from PL(eV) (Col. 1) Layer thickness ( μ m ) (Col. 2) Doping ( cm − 3 ) ( p type) Col. 3 Ordering (Col. 4) TRPL lifetime(ns) (Col. 5) L D ( μ m ) (Col. 6) Minority mobility ( cm 2 / V s ) (Col. 7) A GaIn 0 ⋅ 496 P 1.896 0.80 2.7 × 10 17 Disordered 10.2 4.4 730 B GaAs 1.422 1.90 9.7 × 10 15 20.3 17.1 5560 C GaIn 0.01 As 1.409 1.90 1.1 × 10 16 433 56.4 2840 D GaIn 0 ⋅ 496 P 1.807 0.65 1.1 × 10 17 Ordered Perpendicular 13.1 3.9 450 Parallel 13.1 3.1 280 FIG. 1. Three-dimensional images of spatial variation of recombination of minority carriers (electrons) in p -type double heterostructures reflecting diffusion from a quasipoint source for three different materials. FIG. 2. Semilogarithmic plot of intensity distribution as a function of position; data represent one diameter of the symmetric diffusion profiles from Fig. 1 . FIG. 3. Comparison of the experimental data (points) to the asymptotic fits (solid colored lines) for the determination of the minority-carrier diffusion length for the three materials of Fig. 1 . FIG. 4. Comparison of the experimental data (points) to the asymptotic fits (solid colored lines) for diffusion perpendicular to and parallel to the ordering direction of GaInP. Inset: two-dimensional image of recombination distribution showing anisotropy of minority-carrier diffusion. FIG. 5. Measured diffusion lengths and related mobility-lifetime ( μ τ ) products as a function of temperature for transport both perpendicular (▲) and parallel (◼) to the ordering direction for ordered GaInP. ",
year = "2009",
doi = "10.1063/1.3068196",
language = "English (US)",
volume = "105",
journal = "Journal of Applied Physics",
issn = "0021-8979",
publisher = "American Institute of Physics Publising LLC",
number = "2",
}