Broad photoluminescence band in undoped AlxGa1−xAs grown by organometallic vapor phase epitaxy

Abstract

We have studied the 77 K photoluminescence ͑PL͒ of undoped-Al x Ga 1Ϫx As (0.21рxр0.83) grown by organometallic vapor phase epitaxy. A deep broad ͑DB͒ PL band is found at 1.6-1.7 eV at a range of x from 0.21 to 0.63, with a maximum intensity at around xϭ0.5. Its large full width at half-maximum (ϳ200 meV) suggests that this emission originates from some impurity-defect complex. The Si-and C-doping dependencies of the PL reveal that the emission disappears in Si-doped n-type samples while it increases in intensity superlinearly with the hole concentration, thus, the emission center is C acceptor related. Furthermore, annealing Al 0.52 Ga 0.48 As samples in H 2 flow eliminates the emission, while annealing in AsH 3 flow increases the emission. Based on these results, we have considered the doping and V/III dependencies of various major point defects present in p-type GaAs and those of the combinations of the C acceptor and these defects. It is concluded that the DB band originates from the substitutional C-As antisite complex (C As -As Ga ). Mass-action rule analysis of the complex deduces a quadratic increase in the PL intensity with hole concentration, which generally explains the experimental results. © 1997 American Institute of Physics. ͓S0021-8979͑97͒06211-7͔

Mitigation of parasitic leakage current in indoor perovskite photovoltaic modules using porous alumina interlayer

“…To investigate light‐dependent recombination, the integrated PL intensity under various excitation powers was measured. The integrated PL intensity is directly related to the excitation power through a power index, represented by the formula , where I is integrated PL intensity, P is excitation power, and F is the parameter reflected in the various recombination processes 47 . An F value of 1 indicates that radiative recombination dominates.…”

“…The integrated PL intensity is directly related to the excitation power through a power index, represented by the formula I / P F , where I is integrated PL intensity, P is excitation power, and F is the parameter reflected in the various recombination processes. 47 An F value of 1 indicates that radiative recombination dominates. Otherwise, if F >1, the SRH recombination dominates owing to the presence of nonradiative recombination center, which act as defects.…”