Power- and temperature-dependent photoluminescence investigation of carrier localization at inverted interface transitions in InAlAs/InP structures

Abstract

We report on combined photoluminescence (PL) and micro-Raman microscopy to study the effect of the V/III flux ratio on InAlAs ternary alloy grown on (311)A InP by metal-organic chemical vapor deposition. The PL of the type-II transition was studied in a wide range of temperatures (10–300 K) and excitation intensities. As the V/III flux ratio increased from 25 to 125, a redshift of the type-II transition was observed. Then, micro-Raman investigations showed the presence of an LO mode related to LO-like InAs in InAsP alloy at the inverted interface in our samples. Furthermore, we discuss the effect of laser excitation wavelength on the Raman spectrum. We also note that phonon peaks are very sensitive to different excitation sources (364 to 638 nm). At lower frequencies, disorder-activated longitudinal acoustic phonons are also observed, which consider the presence of potential fluctuations. This last generate the carrier’s localization, which confirmed by PL measurements. In all samples, a blueshift of the type-II transition is noted with increasing the excitation power, which may reflect the presence of carrier localization, whereas the temperature-dependent PL peak energy displayed unusual behavior, such as consecutive red–blue–redshift (S-shaped) behavior and an inverted N-shape in the full width at half maximum. These unusual behaviors are explained by carriers captured by localized recombination centers. Moreover, in the room temperature PL spectra two types of emission were detected at 1.3 and 1.55 μm.

Gallium Phosphide Nanowires Grown on SiO2 by Gas-Source Molecular Beam Epitaxy

“…For process (II), the exciton binding energy Δ E is the activation energy, including both the free exciton energy and the binding energy of the free excitons to the trap centers. Therefore, we apply the Arrhenius model to estimate the activation energy . The integrated PL intensity of the energy peak at 2.14 eV as a function of temperature can be described by I = I 0 1 + A nobreak0em0.25em⁢ exp ( − E a / k B T ) where A is the non-radiative recombination process coefficient, k B is again the Boltzmann constant, and E a is the activation energy for thermal dissociation of the bound excitons …”

“…Therefore, we apply the Arrhenius model to estimate the activation energy . The integrated PL intensity of the energy peak at 2.14 eV as a function of temperature can be described by I = I 0 1 + A nobreak0em0.25em⁢ exp ( − E a / k B T ) where A is the non-radiative recombination process coefficient, k B is again the Boltzmann constant, and E a is the activation energy for thermal dissociation of the bound excitons Figure d shows the integrated PL intensity as a function of 1/ k B T and the fitting curve using the Arrhenius equation, which results in a thermal activation energy of 31 ± 3 meV for trap-bound excitons in WZ GaP NWs.…”

Different spectral features near the energy bandgaps of normal and inverse heterostructures of In_0.52Al_0.48As/InP

“…InAlAs/InP异质 结界面性质一直是长期受到关注且比较复杂的材 料生长和器件物理问题 [6] . 例如异质结的外延生长 中常常伴随着界面处As/P原子的交换和In, As 原子的自聚团簇效应, 这导致其界面光谱现象具有 复杂性而其产生机制也有不同的观点 [7][8][9][10][11][12][13][14][15][16][17] .…”

“…和反向界面结构的不同 [8][9][10][11] , 它是由两类界面生长 时发生的In-As-P原子的不同扩散机制所导致. 结 合现有文献关于InAlAs/InP正向界面和反向界面 电子结构的描述 [7][8][9][10][11][12][13][14]16] 过程, 即图3所示的过程③, 类似发光过程在其他 半导体异质结如GaN/AlGaN结构的研究中同样 存在 [23] .…”