Hydrogen Passivation of Defects in InGaAs/AlxGal-xAs Quantum Wells

1992 ◽  
Vol 262 ◽  
Author(s):  
S. M. Lord ◽  
G. Roos ◽  
B. Pezeshki ◽  
J. S. Harris ◽  
N. M. Johnson

ABSTRACTThe effect of the diffusion of monatomic hydrogen into InGaAs/AlGaAs quantum wells has been investigated using photoluminescence (PL) and Secondary Ion Mass Spectroscopy (SIMS). The structures were grown by molecular beam epitaxy and hydrogenated with a remote plasma. For In0.2Ga0.8AlxGA1-xAs quantum wells, hydrogenation significant increases the integrated PL intensity from bound excitons at 77 K. The enhancement of the PL is ascribed to removal of nonradiative recombination centers by hydrogen passivation of defects either at the heterojunction interface or within the epilayers. This PL enhancement (and defect passivation) increases as the Al concentration in the AlGaAs layers increases from 0 to 33 at%. A 50% increase of PL intensity is observed for InGaAs/GaAs. For 33 at%, the increase is a factor of 9. We also diffused deuterium into these InGaAs/AlGaAs quantum wells. The enhancement of the PL by deuteration was similar to that by hydrogenation. The isotopie substitution permits the determination of the depth distribution of deuterium in the multilayered structure by SIMS. SIMS results support the conclusion that more defects are passivated in the higher Al concentration samples.

1995 ◽  
Vol 395 ◽  
Author(s):  
Y. Li ◽  
Y. Lu ◽  
H. Shen ◽  
M. Wraback ◽  
C.-Y. Hwang ◽  
...  

ABSTRACTThe effects of hydrogen passivation in MOCVD grown Mg doped p-type GaN were studied using low temperature (5K) photoluminescence (PL) and secondary-ion-mass spectroscopy (SIMS). GaN films with different Mg doping level were annealed at 700° C in N2 ambient with different annealing times. The SIMS results indicate that the hydrogen concentration increases with increasing Mg doping level in the as-grown Mg:GaN film. After 20 minutes of annealing, most of the hydrogen escapes from the film. The 3.455 eV PL peak before annealing and the 3.446 eV peak after annealing found in the Mg doped samples were attributed to the exciton bound to the Mg-H complex and to the Mg acceptor, respectively. The shift of the bound exciton peak to higher energy (3.465 eV) in the lightly doped sample is due to an effective n-type compensation associated with an annealing-induced increase in the nitrogen vacancies. In heavily doped Mg:GaN, the decreases in the integrated PL intensity after 700° C annealing may be associated with the hydrogen depassivation of nonradiative recombination centers in the film. The increase of PL intensity in the lightly doped sample after annealing is attributed to the reduction of defects by the annealing process.


Author(s):  
Norihiko Kamata ◽  
Abu Zafor Md. Touhidul Islam

We have developed an optical method of detecting and characterizing nonradiative recombination (NRR) centers without electrical contact. The method combines a below-gap excitation (BGE) light with a conventional above-gap excitation light in photoluminescence (PL) measurement, and discriminates the PL intensity change due to switching on and off the BGE. A quantitative analysis of the detected NRR centers became possible by utilizing the saturating tendency of the PL intensity change with increasing the BGE density due to trap filling effect. Some experimental results of AlGaAs, InGaN, and AlGaN quantum wells were shown to allocate the development and present status as well as to exemplify their interpretations.


2007 ◽  
Vol 31 ◽  
pp. 74-76 ◽  
Author(s):  
P.T. Huy ◽  
P.H. Duong

Photoluminescence (PL) from silicon nanocrystals deposited on top of silica-glass template and from silicon nanocrystals in nc_Si/SiO2 multilayer films were studied as a function of ultraviolet (UV) laser irradiation time in vacuum. Both the films exhibit intense visible PL at room temperature under laser excitation. It was found that upon prolong irradiation time using a He-Cd laser (325 nm) the PL intensity of the films was spectacularly enhanced. The process is reversible and does not happen with excitation wavelength longer than 400 nm. Upon introducing air into the measurement chamber, a rapid decrease of the PL intensity was recorded. This observation suggests that the UV light may lead to modification of nonradiative recombination centers in the films and thus improves the emission yield of silicon nanocrystals.


2019 ◽  
Vol 58 (SC) ◽  
pp. SCCB37 ◽  
Author(s):  
M. Ismail Hossain ◽  
Yuri Itokazu ◽  
Shunsuke Kuwaba ◽  
Norihiko Kamata ◽  
Noritoshi Maeda ◽  
...  

2014 ◽  
Vol 11 (3-4) ◽  
pp. 832-835 ◽  
Author(s):  
A. Z. M. Touhidul Islam ◽  
N. Murakoshi ◽  
T. Fukuda ◽  
H. Hirayama ◽  
N. Kamata

Author(s):  
Shigefusa F. Chichibu ◽  
Hideto MIYAKE ◽  
Akira Uedono

Abstract To give a clue for increasing emission efficiencies of Al x Ga1-x N-based deep ultraviolet light emitters, the origins and influences on carrier concentration and minority carrier lifetime (τminority), which determines the internal quantum efficiency, of midgap recombination centers in c-plane Si-doped Al0.60Ga0.40N epilayers and Al0.68Ga0.32N quantum wells (QWs) grown by metalorganic vapor phase epitaxy were studied by temporally and spatially resolved luminescence measurements, making a correlation with the results of positron annihilation measurement. For the Al0.60Ga0.40N epilayers, τminority decreased as the concentration of cation vacancies (VIII) increased, indicating that VIII, most probably decorated with nitrogen vacancies (VN), VIII(VN) n , are major nonradiative recombination centers (NRCs). For heavily Si-doped Al0.60Ga0.40N, a generation of electron-compensating complexes (VIII-SiIII) is suggested. For lightly Si-doping regime, τminority of the QW emission was increased by appropriate Si-doping in the wells, which simultaneously increased the terrace width. The importance of wetting conditions is suggested for decreasing the NRC concentration.


2019 ◽  
Vol 33 (06) ◽  
pp. 1950032
Author(s):  
D. V. Gulyaev ◽  
K. S. Zhuravlev

Mechanisms of exciton photoluminescence (PL) quenching in the longitudinal electric field of a standing surface acoustic wave (SAW) have been studied by the example of type II GaAs/AlAs superlattices (SLs). Such SLs with a long lifetime of nonequilibrium carriers have allowed examining the influence of the SAW electric field on the excitonic PL both under the continuous and impulse laser excitations. It has been found that the mechanisms of the interaction of excitons and a SAW electric field depend upon the kinetic energy of excitons and carriers. As for hot excitons and carriers, the standing SAW electric field causes the impact ionization of excitons with a subsequent capture of free carriers at the nonradiative recombination centers, which results in a decrease in the steady-state exciton PL. As for cold excitons and carriers, the impact of excitons with the carriers accelerated by the SAW electric field results mainly in exciton delocalization from the levels of quantum wells formed due to interface roughness with a subsequent capture of excitons at the nonradiative recombination centers, which leads to the acceleration of the PL kinetics.


Author(s):  
Д.С. Абрамкин ◽  
М.О. Петрушков ◽  
М.А. Путято ◽  
Б.Р. Семягин ◽  
Е.А. Емельянов ◽  
...  

AbstractMolecular-beam epitaxy is used to produce GaP/Si hybrid substrates that allow the growth of highly efficient light-emitting heterostructures with GaAs/GaP quantum wells. Despite the relatively high concentration of nonradiative-recombination centers in GaP/Si layers, GaAs/GaP quantum-well heterostructures grown on GaP/Si hybrid substrates are highly competitive in terms of efficiency and temperature stability of luminescence to similar heterostructures grown on lattice-matched GaP substrates.


Sign in / Sign up

Export Citation Format

Share Document