PMT signals of InP(S) transmission luminescence: (a) normalized; wafer with carrier concentration of at different temperatures (K) and (b) wafers of various doping concentration (in units of ) at a fixed excitation wavelength (the time scale is expanded for better resolution of the short signals in higher concentration samples).
Luminescence spectra for cw excitation [(a)–(c)] at 640 nm (1.94 eV) and time-integrated OPO excitation (d). (a) Reflection (amplitude decreases with concentration) and transmission (smaller curves in the same order) spectra for different carrier concentrations (in units of ); (b) evolution of the reflection spectra with temperature for [amplitude decreases with increasing temperature (K)]; (c) normalized reflection and transmission (T) spectra (solid curves) for at 78 and 300 K together with the corresponding transmission factors , where is the thickness of the wafer (dashed curves). (d) Reflection spectra from a sample with for different excitation photon energies (eV) at room temperature (OPO excitation).
Absorption coefficient for different photon energies and carrier concentrations , . (a) Experimental absorption spectra (solid curves) with their interpolations to higher energies (dash-dot curves) from Ref. 22, see details in the text. The wafer was thinned down to enabling measurements of up to . Triangles correspond to an undoped sample (from Ref. 17). (b) Concentration dependence of the absorption coefficient at the photon energy .
Luminescence decay rates measured by kinetic experiments and approximated by superposition of two power functions of concentration and temperature [Eq. (3)]. (a) Temperature dependence of the luminescence decay rate for different doping concentrations in units . Dashed lines represent fits to the experimental data as in Eq. (3). For , the experimental point at deviates from the approximation because of the limited detector resolution. (b) The concentration dependence of the coefficients and with approximations by quadratic polynomials. Triangles at correspond to the data of Ref. 4.
Concentration dependence of the recycling factor (squares) and quantum efficiency (dots) obtained from the experimental data. The dashed curves are analytical approximations, and in terms of coefficients , , , and .
Photon escape factor out of the detection area, free-carrier absorption factor , and the effective recycling factor at .
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