Determination of chemical composition and average crystal lattice constants of InGaN/GaN multiple quantum wells

Abstract

The samples of InGaN/GaN multiple quantum wells (MQWs) have been grown on (0001) sapphire substrate with n-GaN buffer layer by metal-organic chemical vapor deposition (MOCVD). According to the results of Rutherford backscattering (RBS)/channeling along 〈0001〉 axis, the conventional θ—2θ scans normal to GaN (0004) and (1014) plane at 0° and 180° azimuth angles and the photoluminescence (PL) properties at room temperature, we concluded that In atoms in the InGaN/GaN MQWs are highly substituted, with the substitution rate over 99%, and the average crystal lattice constants of InGaN/GaN MQWs were calculated accurately (aepi=0.3195nm，cepi=0.5198nm), which are almost equal to theoretical data. Using HRXRD and RBS,the atomic content of In was determined to be respectively 0.023 and 0.026, the result was consistent with actual growth conditions of InGaN/GaN MQWs. However,there was a great difference compared with In chemical composition obtained by PL properties, which shows that PL properties are not suitable for measuring the In chemical composition in InGaN/GaN MQWs.

Evaluation of both composition and strain distributions in InGaN epitaxial film using x-ray diffraction techniques

“…The x-ray diffraction (XRD) is now well established as a powerful and nondestructive tool for structural characterization. [11] It is especially suitable for making strain and lattice parameter evaluation in comparison with other methods due to its high sensitivity to lattice plane displacements. The chemical composition of InGaN films has commonly been estimated from peak position of XRD (00l) reflection in ω-2θ mode by applying Vegard's law.…”

Microstructure and strain analysis of GaN epitaxial films using in-plane grazing incidence x-ray diffraction

“…Another prominent advantage of the x-ray method is the high sensitivity to strain with a resolution of ppm level and it is particularly applicable to evaluate strain distribution and lattice parameter in the epitaxial film system. [13] Conventional x-ray Bragg diffraction describes the structural properties perpendicular to the wafer surface or inclined at an angle to it. However structural information parallel to the wafer surface cannot be directly measured.…”

InAs/InGaAs/InAlAs interband quantum well infrared photodetector (IQWIP) with cut-off response wavelength at 1.93μm

“…Here, the Δθ P determined from the angle between the satellite peaks is 0.19°and θ B is the Bragg angle of the InP (004) diffraction. 19,20) Normalized relative spectral response curve was tested by Bruker VERTEX 80 Fourier transform infrared spectrometer at room temperature under zero-bias. The testing was conducted under front-side illumination and with no antireflection coating applied.…”