Inhomogeneities of InGaN/GaN MOVPE multi quantum wells grown with a two temperatures process studied by transmission electron microscopy
✍ Scribed by Kret, S. ;Ivaldi, F. ;Sobczak, K. ;Czernecki, R. ;Leszczyński, M.
- Book ID
- 105365748
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 458 KB
- Volume
- 207
- Category
- Article
- ISSN
- 0031-8965
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
The structural investigation of InGaN/GaN:Si multiple quantum well (MQW) samples grown by low‐pressure metal‐organic vapor phase epitaxy (LP‐MOVPE) in a two temperatures (2__T__) process on high‐pressure GaN mono‐crystalline substrates is performed by transmission electron microscopy (TEM). A sample in which barriers and wells were grown at 780 °C is compared with another in which the barriers were deposited at 900 °C and the wells at 730 °C. For both samples the indium composition in the QWs reaches the level of about 20 at.%. The local indium composition was measured through strain measurements by digital processing from the lattice fringes images taken by TEM. Cross‐sectional investigations are performed in two zone axes – [$1\bar {1}00$] and [$11\bar {2}0$] – with the use of axial and off‐axis illumination. During TEM investigations the formation of “false indium clusters ” of the size of 2–4 nm was observed for both samples just after 2 min of LaB6 electron beam illumination at 200 kV. Large lateral fluctuations of indium content in the QWs of the length of 30–130 nm were detected in 2__T__ sample. The plan view analysis was carried out to characterize the anisotropy of the indium fluctuation inside the QWs.