Temperature Dependence Of Carrier Lifetime Research Articles

Temperature and spatial dependence of carrier lifetime and luminescence intensity in Ge0.95Sn0.05 layer

In this work we present a study of spatial and temperature dependencies of carrier lifetime and photoluminescence in pseudomorphic Ge0.95Sn0.05 layer on silicon by applying contactless time-resolved differential absorption and photoluminescence techniques. The observed small lifetime and photoluminescence intensity spatial variations (~10%) indicate for good material homogeneity. Differential transmission kinetics exhibit fast bleaching and slow absorption components related to thermalization (few hundreds of picoseconds) and surface recombination (few tens of nanoseconds) processes. Temperature dependent photo-luminescence measurements indicate activation of carriers from L to Γ valley, governing dominant direct photoluminescence emission band at 1850 nm at 300 K. These direct transitions explain more efficient and blue-shifted by 150 nm photoluminescence emission at room temperature. At low temperatures direct emission is related to non-thermalized carriers, while indirect one is caused by depopulation of light hole band with temperature.

Temperature dependence of current–voltage and carrier lifetime characteristics in InGaN blue light-emitting diode

In this report, we have measured current–voltage (I–V) and carrier lifetime characteristics of an InGaN-based commercial blue light-emitting diode in a temperature range from 350 to 110 K. Two distinctly different current domains, namely, region I and region II have been identified in I–V dependence. I–V data for region I have been used for the evaluation of ideality factor which varies from 1.478 to 3.932 when the temperature changes from 350 to 110 K. We have also investigated how far the existing models account for our experimental results. From an analysis of the Arrhenius plot of I–V–T curves in terms of the model due to Hirsch and Barriere it is found that the domains are distinguished by current transport mechanisms governed by hole thermionic emission and hole tunneling which are discussed in detail. Next, estimating the data on voltage gradient obtained from the open circuit voltage decay method, as well as those of ideality factor from the I–V measurement, the temperature dependence of carrier lifetime has been evaluated. A logarithmic plot of carrier lifetime as a function of inverse temperature shows a weak temperature-dependence below 228 K and this region gives important information regarding the dominant energy level of traps assisting tunneling of current carriers in the device.

Modeling the temperature characteristics of InAs/GaAs quantum dot lasers

A systematic investigation of the temperature characteristics of quantum dot lasers emitting at 1.3 μm is reported. The temperature dependence of carrier lifetime, radiative efficiency, threshold current, differential efficiency, and gain is measured, and compared to the theoretical results based on a rate equation model. The model accurately reproduces all experimental laser characteristics above room temperature. The degradation of laser characteristics with increasing temperature is clearly shown to be associated to the thermal escape of holes from the confined energy levels of the dots toward the wetting layer and the nonradiative recombination therein.

Recombination dynamics of luminescence in colloidal CdSe/ZnS quantum dots

Recombination dynamics of photoluminescence (PL) in colloidal CdSe/ZnSquantum dots (QDs) were studied using time-resolved PL measurements. ThePL intensity shows a biexponential decay at 9 K, consisting of a fast component(∼1 ns) and a slowcomponent (∼6.3 ns). Based on the emission-energy and temperature dependence of carrier lifetimes, wesuggest that the fast and slow PL decay of colloidal CdSe/ZnS QDs originates fromrecombination of the delocalized carriers in the internal core states and the localizedcarriers at the interface, respectively.

Temperature dependence of carrier lifetimes in InN

AbstractTime‐resolved pump–probe transmission measurements were used to determine the temperature dependence of carrier lifetime for InN epilayers with unintentionally doped levels from 1018 to 1019 cm–3. The observed decay time at 20 K is well explained by a dominating radiative interband recombination, while at room temperature it is attributed to a defect related nonradiative recombination channel. The temperature dependence of the radiative lifetime is deduced from the measurements of both differential transmission decay time and PL intensity. For the best quality sample, we find the radiative lifetime increases proportionally to T3/2, as theory predicts when a k‐selection rule holds, which suggests that the radiative band‐to‐band transition accounts for the observed infrared photoluminescence over the entire temperature. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Recombination activity of iron-related complexes in silicon studied by temperature dependent carrier lifetime measurements

Carrier recombination centers related with iron complexes in p-type silicon are studied by microwave and light-induced absorption techniques. Both thermal- and photoactivation are used to decompose iron–boron pairs and to study the impact on the recombination lifetime. Due to photodissociation of iron–boron pairs the lifetime increases for high level injection. Efficient recombination occurs via an acceptor level at Ec−0.29 eV as derived from the temperature dependence of carrier lifetime.

Recombination activity of iron related complexes in silicon

Recombination centres related to Fe complexes in p type Si are studied by carrier lifetime measurements using non-destructive microwave and light induced absorption techniques. The cross correlation of lifetime, density of electrically active Fe species, and structural defects is used to investigate the transformation and the precipitation of indiffused Fe. The recombination activity of Fe related defects isfound to depend on the injection level of excess carriers. Both thermal and photoactivation mechanisms are employed to decompose Fe–B pairs and to study the impact on the recombination time. The increase of high level injection lifetime due to photodissociation of Fe–B pairs is explained by a more efficient recombination via an acceptor level at Ee – 0.29 eV which has been derived from the temperature dependence of carrier lifetime. The mechanism of a recombination enhanced defect reaction is discussed on the basis of the experimental observations.

Recombination activity of iron related complexes in silicon

Recombination centres related to Fe complexes in p type Si are studied by carrier lifetime measurements using non-destructive microwave and light induced absorption techniques. The cross correlation of lifetime, density of electrically active Fe species, and structural defects is used to investigate the transformation and the precipitation ofindiffused Fe. The recombination activity of Fe related defects is found to depend on the injection level of excess carriers. Both thermal and photoactivation mechanisms are employed to decompose Fe-B pairs and to study the impact on the recombination time. The increase of high level injection lifetime due to photodissociation ofFe-B pairs is explained by a more efficient recombination via an acceptor level at E C -0.29 eV which has been derived from the temperature dependence of carrier lifetime. The mechanism ofa recombination enhanced defect reaction is discussed on the basis of the experimental observations. MST/3312

Temperature dependence of photoluminescence lifetimes in ordered GaInP2

The temperature dependence of carrier lifetimes in ordered (o) GaInP2 epilayers was investigated with and without cladding layers of disordered (d) GaInP2. The extremely long lifetime of the emission that moves with laser excitation density and the shorter lifetime of the nonmoving emission persist up to T=50 and 300 K, respectively. Both decays involve localized holes. By removal of the d top layer of the double heterostructure, an enhanced hole diffusion to the surface occurs, which results in a slightly faster, nonexponential decay. It is argued that, within the nominally o layer, a type II recombination occurs and that o and d GaInP2 exhibit a type II band lineup. The appropriate band curvatures in the d top layer cause hole localization at the d side of the o–d interfaces. The minority carrier lifetime shows two-dimensional behavior between T=70 and 170 K, and decrease above 170 K.

A unified mobility model for device simulation—II. Temperature dependence of carrier mobility and lifetime

In Part I we presented the first physics-based analytical model that unifies the descriptions of majority and minority carrier mobility and that includes screening of the impurities by charge carriers, electron-hole scattering and clustering of impurities. Here the model is extended to include the full temperature dependence of both majority and minority carrier mobility. Based on our model and experimental data on the minority carrier diffusion length as a function of temperature, the temperature dependence of the carrier lifetime is determined. The model is especially suited for device simulation purposes, because the carrier mobility is given as an analytical function of the donor, acceptor, electron and hole concentrations and of the temperature.

Linear and two-photon absorptions of Si-Ge strained-layer superlattices

Linear and two-photon absorption spectra of Si-Si0.5Ge0.5 strained-layer superlattices grown along [001], [111], [110] directions are calculated within a realistic microscopic model. The temperature dependence of carrier lifetimes due to deformation-potential scattering (including intra- and intervalley scattering) has been taken into account. It is found that superlattices grown along the [110] direction are most promising for applications both in far-infrared detection and in optical limiting. The value for the two-photon absorption coefficient at 77 K for an incident 10.6-μm radiation polarized parallel to the layer can be as high as 150–2000 cm/MW with a linear absorption coefficient around 600–3500 cm−1.

Temperature dependence of carrier lifetime and Auger recombination in 1.3 μm InGaAsP

Carrier lifetime has been measured by the luminescence decay of a 1.3-μm-InGaAsP layer excited by a mode locked YAG laser at 1.06 μm. The measurements have been done as a function of excitation intensity for nearly three orders of magnitude of carrier concentration (4×1016–2×1019 cm−3) and for different temperatures (between 32 and 346 K). At low and moderate carrier density, the lifetime τ follows the variation with excitation of the theoretical radiative lifetime. At high carrier density (above 1018 cm−3) the carrier decay rate increases more rapidly than the radiative one and around room temperature this can be accounted for by an additional recombination mechanism whose variation with excitation is typical of an Auger process. The Auger coefficient (Ca=2.6×10−29 cm6 s−1) does not vary with temperature within experimental uncertainty. This suggests that though Auger recombination is for a large part responsible for the low T0 value of 1.3-μm InGaAsP lasers, the temperature dependence of the Auger coefficient does not contribute to it.

Temperature Sensitive Threshold Current of InGaAsP–InP Double Heterostructure Lasers

The threshold current of InGaAsP–InP double hetetostructure lasers has been investigated through measurements of the temperature dependence of carrier lifetime and radiative efficiency. Both the carrier lifetime and the radiative efficiency decrease noticeably above the break point temperature as observed in the Ith vs. T relation. The decrease of the carrier lifetime is explained by considering additional non-radiative recombination centers with 0.3 eV activation energy. The origin of this center is also discussed.

Effects of Impurities on Gamma-Irradiated Silicon Crystal Examined by Photovoltaic Effect of P-N Junction Diode

Minority carrier lifetime in 60Co gamma-irradiated silicon bulk crystals is examined by photovoltaic effect of silicon p-n junction, and following results are disclosed. 1) Damage constant, K, increases with impurity concentration of bulk crystals. K is smaller in p-type crystals than in n-type. 2) For isochronal annealing, recovery stages of n-type bulk crystals at 100–150°C and 300°C are found. In p-type crystals, reverse annealing is observed at 200–300°C. 3) From the temperature dependence of carrier lifetime, energy levels of the recombination centers at Ec-0.42 for n-type and Ev+0.32, Ev+0.25 eV for p-type crystals are found. 4) Recovery stage of p-type bulk crystals due to gamma irradiation at 81 K is observed at about 150 K, but that of n-type is not observed between 80 and 300 K. 5) The lifetime degradation in p-type crystals due to gamma irradiation at 81 K is reduced when minority carrier is injected after the irradiation.

Temperature dependence of carrier lifetime in silicon power devices

Temperature dependence of carrier lifetime in silicon power devices

Temperature Dependence of Carrier Lifetime in Silicon

Measurements of carrier lifetime have been made on both n- and p-type silicon crystals over the temperature range 0°C to 200°C. Results are given for both high and low values of injected carrier concentrations. A comparison is made with the Shockley-Read picture of carrier recombination. The results and theory may be reconciled on the assumption that the capture probabilities of the recombination centres are temperature dependent, and that the energy levels of the centres lie 0.45±0.05 eV above the valence band.