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(a) Photography of sample MT2433; (b) experimental setup; (c) evolution of IR signal under different excitation (sample MT2433): (c.1) no excitation, IR background is measured, (c.2) IR PL signal under 532 nm excitation (5 mW), (c.3) an enhancement of the IR signal is measured under a pulsed electrical excitation (−800 V@15 Hz) with the same optical excitation, (c.4) with only an electrical excitation no IR signal is measured, IR signal is comparable to IR background.
IR emission measured as a function of depth in the sample (the origin is at the cathode location). The PL is collected from the emitting side of the sample for different electrical biases and for an optical excitation at 532 nm of 5 mW. Images obtained with the IR camera are shown, illustrating the emission localization at the cathode. (sample MT2443).
Indicative band diagram of Cr:ZnSe under bias with mechanisms of excitation of . The band curvature is explained by the presence of negative charges in the structure. In presence of , the main processes are: hole-recombination [Eq. (2)] and photoexcitation [Eq. (3)]. Under an electrical bias, photogenerated holes will be drifted toward the cathodes and thus will enhanced the recombination on .
Measurements of enhanced IR PL at the cathode (dots) as a function of the optical power illuminating the sample, solid lines are calculations based on a two states model [Eq. (5), sample MT2453]. The inset shows the same measurements (dots) against the electrical bias applied to the sample. A quadratic law can be deduced from these data (solid lines).
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