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Spectroscopie des processus photoélectriques dans les structures et dispositifs III-N

Abstract : In spite of the rapid technological progress in nitrides, the intrinsic properties of nitride alloys and the physics of III-N devices are still not well understood. In the course of my thesis work, novel experimental and theoretical approaches to tackle the study of the microscopic mechanisms governing the electronic properties of nitride semiconductors have been developed. A new experimental technique allowing to directly measure the energy distribution of conduction electrons of an operating LED is explored. This approach allows the direct observation of hot electron populations excited in the optoelectronic device under electrical operation and emitted in ultra-high vacuum. A recent theory of localization in disordered systems is applied to nitride materials and optoelectronic devices. This method allows for the first time the determination of the localization landscape induced by alloy disorder without resorting to the Schrödinger equation. Experimentally, a clear signature of alloy disorder is observed by biased photocurrent spectroscopy of InGaN quantum wells in the form of an Urbach tail for below-gap excitation and is found to be in excellent agreement with the predictions given by the novel localization theory.
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Submitted on : Thursday, January 12, 2017 - 4:46:06 PM
Last modification on : Monday, October 19, 2020 - 10:52:44 AM
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  • HAL Id : tel-01433533, version 1


Marco Piccardo. Spectroscopie des processus photoélectriques dans les structures et dispositifs III-N. Autre [cond-mat.other]. Université Paris Saclay (COmUE), 2016. Français. ⟨NNT : 2016SACLX056⟩. ⟨tel-01433533⟩



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