Indium concentration fluctuations in InGaN/GaN quantum wells

Abstract

Secondary ion mass spectrometry measurements can provide specific information on In fluctuations in InGaN quantum wells.

Defects and Reliability of GaN‐Based LEDs: Review and Perspectives

“…Finally, an important observation concerns the difficulty of growing InGaN layers with a homogeneous indium concentration [ 79 ] : this could lead to fluctuations in the indium molar content within the QW, thus altering the ideal charge distribution and the peak emission wavelength. [ 80 ]…”

Atomic spectrometry update: review of advances in the analysis of metals, chemicals and materials

“…Igarashi reported the rst Pu isotope measurements in radioactive particles released during the accident to determine whether nuclear fuel radionuclides were present. 210 Radioactive particles from units 1, 2 and 3 were measured using ICP-MS, with Pu only detected in unit 1 materials at activities of 1.70-7.06 Â 10 À5 Bq for 239+240 Pu and 4.10-8.10 Â 10 À3 Bq for 241 Pu, with atom ratios consistent with ORIGEN (a computer code system for calculating the build-up, decay, and processing of radioactive materials) calculations and environmental measurements. The difference in results between samples showed the value in measuring Pu isotopes for monitoring particle formation processes.…”

“…Eppich et al focused on Pu isotopes in environmental swipe samples measured using MC-ICP-MS following digestion and chemical separation. 203 The method was validated using reference materials, with a precision of <1% achieved for 240 Pu/ 239 Pu, 241 Pu/ 239 Pu and 242 Pu/ 239 Pu at a ratio of $6.3 Â 10 À2 . A 239 Pu detection limit of 0.10-0.58 fg was calculated, with an expanded uncertainty averaging 1.7% in swipe samples containing 0.32 fg and 10.5 fg total Pu.…”

Unlocking the origin of compositional fluctuations in InGaN light emitting diodes

“…In-depth studies of atom probe tomography have provided valuable insights on the In distribution in the InGaN QWs [31][32][33][34][35][36] . Extensive atomically-resolved characterization techniques, such as scanning transmission electron microscopy (STEM) [37][38][39][40][41] have proved the absence of large scale (on the order of tens of nanometers) compositional fluctuations. Nevertheless, atomistic-scale investigations using high-resolution electron microscopy suffer from a limited field of view, which hinders the detection of accurate size distribution of potential compositional fluctuations [37][38][39][40][41] , and possible beam-induced structural modifications 42 .…”

“…Extensive atomically-resolved characterization techniques, such as scanning transmission electron microscopy (STEM) [37][38][39][40][41] have proved the absence of large scale (on the order of tens of nanometers) compositional fluctuations. Nevertheless, atomistic-scale investigations using high-resolution electron microscopy suffer from a limited field of view, which hinders the detection of accurate size distribution of potential compositional fluctuations [37][38][39][40][41] , and possible beam-induced structural modifications 42 . Recently, it has been shown that imaging under the knock-on threshold preserves the QW structures 38,43 , allowing the quantification of compositional fluctuations at the sub-nanometer scale.…”