Atom probe analysis of interfacial abruptness and clustering within a single InxGa1−xN quantum well device on semipolar (101¯1¯) GaN substrate

Abstract

Pulsed laser atom probe tomography (APT) of InxGa1−xN single quantum well (SQW) grown on semipolar (101¯1¯) GaN orientation estimates the interior atomic composition within the SQW at 6.5±0.7 at. % In, 46.2±0.7 at. % Ga, and 47.3±0.7 at. % N. The atom probe analysis is performed in both “top-down” and “cross-section” orientations. Self-consistent Schrödinger–Poisson simulation employing structural and compositional parameters obtained from APT results estimates the polarization field within the SQW at 720 kV/cm. A statistical method for the evaluation of indium homogeneity within the SQW is also considered.

Titanium oxide nanoparticles spin-coated onto r-plane sapphire substrate: Effects on structural and optical properties of nonpolar a-plane GaN and InGaN/GaN multiple quantum wells

“…However, Smeeton et al have found that the contrast of HR-TEM images of InGaN/GaN MQWs changes with increasing electron beam exposure time [34]. Further, Galtrey et al [35] and Prosa et al [36] demonstrated no statistically significant deviation from the distribution expected for an In x Ga 1À x N random alloy in In x Ga 1À x N QW with atom probe analysis. According to their reports, the reliable cause of carrier localization in In x Ga 1À x N QW was well width fluctuation at the upper interface between wells and barriers.…”

A graph-theoretic approach for characterization of precipitates from atom probe tomography data

“…Specifically, some of the approaches for precipitate analysis include: (i) proximity histograms, (ii) Fourier analysis, and (iii) friends-of-friends analysis. While chemical analysis of a chosen bin size through proximity histograms is a convenient technique for linking spatial features with chemistry and has shown good results [5,19], the definition of the region analyzed is mathematically arbitrary. The region is defined by a user-defined chemical threshold value, and therefore a precipitate is defined largely through assumption.…”

Advances in the LED Materials and Architectures for Energy-Saving Solid-State Lighting Toward “Lighting Revolution”

“…In the meantime, the lattice mismatch between InGaN and GaN can also be released in the quantum dots (QDs), which leads to a better electron-hole overlap and increased radiative recombination rates [31]. InGaN/GaN wafers grown nonpolar/ semipolar orientation have eliminated the polarization-induced fields [32]- [34], therefore enabling a complete overlap between electron and hole wave functions and an increase in the optical matrix element [35], [36].…”