Crystallization from amorphous structure to hexagonal quantum dots induced by an electron beam on CdTe thin films

Becerril, M.; Zelaya-Ángel, O.; Medina-Torres, A.C.; Aguilar‐Hernández, J.; Ramı́rez-Bon, R.; Espinoza‐Beltrán, F.J.

doi:10.1016/j.jcrysgro.2008.12.056

Cited by 12 publications

(5 citation statements)

References 24 publications

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“…All spectra showed the CdTe longitudinal optical (LO) mode at the frequency of 166.5 cm −1 and their second order (2LO) mode at 333 cm −1 , characteristic of CdTe. 6 The LO modes of cubic and hexagonal phases of CdTe can coincide at the same frequency, 13 so these measurements agree with those of XRD. The features located at 123 and 142 cm −1 correspond to the phonon vibrations A 1 and E 1 modes, respectively, in the hexagonal Te structure.…”

Section: Resultssupporting

confidence: 62%

Structural and optical properties of Cu-doped CdTe films with hexagonal phase grown by pulsed laser deposition

et al. 2012

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Section: Resultssupporting

confidence: 62%

Structural and optical properties of Cu-doped CdTe films with hexagonal phase grown by pulsed laser deposition

et al. 2012

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“…For example, in tip-induced nano-oxidation of metals and semiconductors ,− or electrochemical writing in lanthanum aluminate-strontium titanate interfaces, , once the critical tip bias is established, complex nanostructures can be created. Similarly, an electron beam can be used to crystallize or amorphize semiconductor materials ,− or induce polarization switching in ferroelectrics. , Once the relationship between electron dose and the resultant structures is established, a controlled path scanning can be used to create structures of predefined spatial complexity . A recent overview of such an effort is given in ref .…”

Section: General Considerationsmentioning

confidence: 99%

Automated and Autonomous Experiments in Electron and Scanning Probe Microscopy

et al. 2021

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Machine learning and artificial intelligence (ML/AI) are rapidly becoming an indispensable part of physics research, with domain applications ranging from theory and materials prediction to high-throughput data analysis. In parallel, the recent successes in applying ML/AI methods for autonomous systems from robotics through self-driving cars to organic and inorganic synthesis are generating enthusiasm for the potential of these techniques to enable automated and autonomous experiment (AE) in imaging. Here, we aim to analyze the major pathways towards AE in imaging methods with sequential image formation mechanisms, focusing on scanning probe microscopy (SPM) and (scanning) transmission electron microscopy ((S)TEM). We argue that automated experiments should necessarily be discussed in a broader context of the general domain knowledge that both informs the experiment and is increased as the result of the experiment. As such, this analysis should explore the human and ML/AI roles prior to and during the experiment, and consider the latencies, biases, and knowledge priors of the decision-making process. Similarly, such discussion should include the limitations of the existing imaging systems, including intrinsic latencies, non-idealities and drifts comprising both correctable and stochastic components. We further pose that the role of the AE in microscopy is not the exclusion of human operators (as is the case for autonomous driving), but rather automation of routine operations such as microscope tuning, etc., prior to the experiment, and conversion of low latency decision making processes on the time scale spanning from image acquisition to human-level high-order experiment planning. Overall, we argue that ML/AI can dramatically alter the (S)TEM and SPM fields; however, this process is likely to be highly nontrivial, be initiated by combined human-ML workflows, and will bring new challenges both from the microscope and ML/AI sides. At the same time, these methods will enable fundamentally new opportunities and paradigms for scientific discovery and nanostructure fabrication.

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“…Cadmium telluride (CdTe) is an important II−VI semiconducting material which exists in either zincblende (cubic) or wurtzite (hexagonal) structure with an ideal direct band gap of 1.45 eV at room temperature and an absorption coefficient greater than 1×10 5 cm -1 near the absorption edge, suited for effective photovoltaic energy conversion [1,2]. CdTe can exhibit both n-type and p-type conductivity, which makes it useful for both homo junction and hetero junction configurations.…”

Section: Introductionmentioning

confidence: 99%

Effect of post deposition heat treatment on microstructure parameters, optical constants and composition of thermally evaporated CdTe thin films

Kumarasinghe

Dissanayake

Pemasiri

et al. 2017

Materials Science in Semiconductor Processing

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Thin film microstructure and its properties can be effectively altered with post deposition heat treatments. In this respect, CdTe thin films were deposited on glass substrates at a substrate temperature of 200 °C using thermal evaporation technique, followed by air annealing at different temperatures from 200 to 500 °C. Structural analysis reveals that CdTe thin films have a cubic zincblend structure with two oxide phases related to CdTe 2 O 5 and CdTeO 3 at annealing temperature of 400 and 500 °C respectively. Regardless of the annealing temperature, the plane (111) was found to be the preferred orientation for all films. The crystallite size was observed to increase with annealing temperature. All films were found to display higher lattice parameters than the standard, and hence found to carry a compressive stress. Optical measurements suggest high uniformity of films both before and after post deposition heat treatment. Films annealed at 400 °C displayed superior optical properties due to its high refractive index, optical conductivity, relative density and low disorder. Furthermore, according to the compositional measurements, CdTe thin films were found to exhibit Te rich and Cd rich nature at regions near the substrate and center of the film respectively, for all annealing temperatures. However, composition of the regions near the substrate was found to become more Te rich with increasing annealing temperature. The study suggests that changing the annealing temperature as a post deposition treatment affects structural and optical properties of CdTe thin film as well as its composition. According to the observations, films annealed at 400 °C can be concluded to be the best films for photovoltaic applications due to its superior optical and structural properties.

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Crystallization from amorphous structure to hexagonal quantum dots induced by an electron beam on CdTe thin films

Cited by 12 publications

References 24 publications

Structural and optical properties of Cu-doped CdTe films with hexagonal phase grown by pulsed laser deposition

Structural and optical properties of Cu-doped CdTe films with hexagonal phase grown by pulsed laser deposition

Automated and Autonomous Experiments in Electron and Scanning Probe Microscopy

Effect of post deposition heat treatment on microstructure parameters, optical constants and composition of thermally evaporated CdTe thin films

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