Kinetics of compositional disordering of AlGaAs/GaAs quantum wells induced by low-temperature grown GaAs

Abstract

Compositional disordering of GaAs/AlGaAs quantum wells due to the presence of low-temperature grown GaAs (by molecular beam epitaxy) was studied. Ga vacancy enhanced interdiffusion was found to be the mechanism underlying the observed intermixing. Diffusion equations were solved numerically to obtain the band profile after intermixing. The transition energies in the quantum wells under various annealing conditions were solved and agree very well with the observed photoluminescence emission peaks. The diffusivity of Ga vacancies and that of induced Al-Ga interdiffusion were obtained. The vacancy induced interdiffusion diffusivity was found to have an activation energy of 4.08 eV, which is smaller than the activation energy of interdiffusion diffusivity of normal temperature grown GaAs/AlGaAs heterostructures. This is a clear indication of enhanced interdiffusion due to the presence of low-temperature grown GaAs.

Annealing behaviors of long-wavelength InAs/GaAs quantum dots with different growth procedures by metalorganic chemical vapor deposition

“…This can also be attributed to the high qualities of sample C's GaAs cap layer. Tang et al's work showed that [19], due to the presence of the large amount of vacancies in the low-temperature-grown GaAs layer, the interdiffusion in the InGaAs/GaAs super lattice was noticeably enhanced. Sample B has similar conditions, that is, the vacancies in its low-temperature growth GaAs cap layer enhance the In-Ga intermixing during the annealing which leads to the large blueshift of the PL emission.…”

Влияние термического отжига на фотолюминесценцию структур с InGaAs/GaAs квантовыми ямами и низкотемпературным delta-легированным Mn слоем GaAs

“…Поскольку процесс лазерного осаждения является более неравновесным, чем МЛЭ, и возможны отклонения от стехиометрии, можно полагать, что концентрация вакан-сий может превышать это значение. Согласно оценкам, сделанным нами по формулам, приведенным в [19,20], соответственно коэффициент диффузии марганца и ко-эффициент диффузии вакансий галлия сопоставимы по порядку величины в температурном диапазоне от 425 до 730…”

Effect of Growth Parameters on Composition Distribution in Superlattice-in-Well Structure by Submonolayer Deposition Technique

“…At the same time, this approach results in a significant increase in component intermixing in the process of superlattice preparing due to the diffusion length shortening. Tremendous research effort has been focused to optimize the performance of electronic and optoelectronic devices by postgrowth diffusion technology [5][6][7][8][9][10][11], while less attention has been paid to in situ diffusion in superlattice with barrier layers of submonolayer thickness.…”