Abstract Photoluminescence Decay Research Articles

Temperature and Injection Dependence of Photoluminescence Decay in Midwave Infrared HgCdTe

Photoluminescence decay (PLD) measurements have been performed on mid-wave infrared (MWIR) Hg-vacancy p-doped HgCdTe samples at temperatures ranging from 85 K to 330 K. The doping level is $$p_{0} = 6 \times 10^{15} \;{\hbox{cm}}^{ - 3}$$ at 80 K and the cut-off wavelength is $$\lambda_{\rm{c}} = 4.2\;\upmu{\hbox{m}}$$ at 300 K. The PLD signal has been fitted with a photo-injection level dependent model in order to estimate the contributions from the different recombination mechanisms to the total minority carrier lifetime. Shockley–Read–Hall centers lying in the bandgap at 25 meV from the conduction or the valence band has been found to limit the minority carrier lifetime from 85 to at least 200 K. The value of the Auger 1 lifetime coefficient is extracted from the first instants of signal decay for each temperature and reaches $$G_{\rm{eei}} n_{i}^{ - 3} = 5 \times 10^{ - 26} \;{\hbox{cm}}^{6} \;{\hbox{s}}^{ - 1}$$ at 85 K. The temperature evolution of the different contributions to the lifetime are in accordance with dark current density measurements in HgCdTe photodiodes.

Photoluminescence decay in a-Si: H/a-Si3N4: H multilayers

Abstract Photoluminescence decay has been studied for five a-Si: H/a-Si3N4: H multilayer structures with different well-layer thicknesses of 8, 13, 25, 50 and 400 A and a common barrier-layer thickness of 100 A. The decay curves are compared with that observed for an a-Si: H film with a thickness of 1 pm. At liquid-helium temperature the photoluminescence has a long effective decay time of 2·5 × 10−3s and this is interpreted in terms of recombination of localized excitons. Above liquid-nitrogen temperature the photoluminescence can be described by a double hyperbolic decay function and interpreted as exciton recombination combined with dispersive diffusion originating from a fractal-time random walk and a random walk on a fractal network.

Radiative and non-radiative tunnelling in glow-discharge and sputtered amorphous silicon

Abstract Photoluminescence decay measurements are reported for doped and undoped glow-discharge a-Si, and for a-Si prepared by sputtering in a hydrogenated atmo-sphere. It is concluded that a distribution of radiative lifetimes is present, due either to non-crystalline disorder or to a donor-acceptor pair mechanism. The main competitive mechanism is tunnelling to defects.