Preliminary Remarks and Historical Overview

Afanas’ev, Valery V.

doi:10.1016/b978-0-08-099929-6.00001-4

Cited by 1 publication

(1 citation statement)

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“…What is most interesting is that the photocurrent from these carbon states measured under positive bias is nearly 1 order of magnitude larger than that under negative bias. In the case of oxide gap state excitation, this would mean that most of these states are spatially located close to the surface of the Si substrate 61,62 i.e., the near-interface layer of alumina appears to be heavily carbon contaminated. With further increase of photon energy, one can observe another spectral threshold around hν ≈ 6 eV for both bias polarities associated with the onset of intrinsic photoconductivity (PC) of amorphous Al 2 O 3 63 (number 4 in inset schematic).…”

Section: Chemical and Optical Analyses Of Ald Almentioning

confidence: 99%

Material-Selective Doping of 2D TMDC through Al_xO_y Encapsulation

Leonhardt

Chiappe

Afanasʼev

et al. 2019

ACS Appl. Mater. Interfaces

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For the integration of two-dimensional (2D) transition metal dichalcogenides (TMDC) with high-performance electronic systems, one of the greatest challenges is the realization of doping and comprehension of its mechanisms. Low-temperature atomic layer deposition of aluminum oxide is found to n-dope MoS2 and ReS2 but not WS2. Based on electrical, optical, and chemical analyses, we propose and validate a hypothesis to explain the doping mechanism. Doping is ascribed to donor states in the band gap of Al x O y , which donate electrons or not, based on the alignment of the electronic bands of the 2D TMDC. Through systematic experimental characterization, incorporation of impurities (e.g., carbon) is identified as the likely cause of such states. By modulating the carbon concentration in the capping oxide, doping can be controlled. Through systematic and comprehensive experimental analysis, this study correlates, for the first time, 2D TMDC doping to the carbon incorporation on dielectric encapsulation layers. We highlight the possibility to engineer dopant layers to control the material selectivity and doping concentration in 2D TMDC.

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Section: Chemical and Optical Analyses Of Ald Almentioning

confidence: 99%