“…The lattice constants calculated from the XRD patterns of CdTe 1-x Se x with x = 0–0.4 are shown in Figure 3, with the value for zinc blende CdSe taken from literature [23]. They follow Vegard’s law with a linear dependence on x , with the smaller size of Se compared to Te causing a decrease in lattice constant.…”
Section: Resultsmentioning
confidence: 92%
“…The values are in agreement with literature [10,24], reinforcing the hypothesis that the peak splitting is caused by a small lattice distortion and thereby reduced symmetry.10.1080/14686996.2018.1497403-F0003Figure 3.Lattice constant of CdTe 1-x Se x thin films on glass substrate. The value for zinc blende CdSe ( x = 1) was taken from literature [23].
…”
The performance improvement of conventional CdTe solar cells is mainly limited by doping concentration and minority carrier life time. Alloying CdTe with an isovalent element changes its properties, for example its band gap and behaviour of dopants, which has a significant impact on its performance as a solar cell absorber. In this work, the structural, optical, and electronic properties of CdTe1-xSex films are examined for different Se concentrations. The band gap of this compound changes with composition with a minimum of 1.40 eV for x = 0.3. We show that with increasing x, the lattice constant of CdTe1-xSex decreases, which can influence the solubility of dopants. We find that alloying CdTe with Se changes the effect of Cu doping on the p-type conductivity in CdTe1-xSex, reducing the achievable charge carrier concentration with increasing x. Using a front surface CdTe1-xSex layer, compositional, structural and electronic grading is introduced to solar cells. The efficiency is increased, mostly due to an increase in the short-circuit current density caused by a combination of lower band gap and a better interface between the absorber and window layer, despite a loss in the open-circuit voltage caused by the lower band gap and reduced charge carrier concentration.
“…The lattice constants calculated from the XRD patterns of CdTe 1-x Se x with x = 0–0.4 are shown in Figure 3, with the value for zinc blende CdSe taken from literature [23]. They follow Vegard’s law with a linear dependence on x , with the smaller size of Se compared to Te causing a decrease in lattice constant.…”
Section: Resultsmentioning
confidence: 92%
“…The values are in agreement with literature [10,24], reinforcing the hypothesis that the peak splitting is caused by a small lattice distortion and thereby reduced symmetry.10.1080/14686996.2018.1497403-F0003Figure 3.Lattice constant of CdTe 1-x Se x thin films on glass substrate. The value for zinc blende CdSe ( x = 1) was taken from literature [23].
…”
The performance improvement of conventional CdTe solar cells is mainly limited by doping concentration and minority carrier life time. Alloying CdTe with an isovalent element changes its properties, for example its band gap and behaviour of dopants, which has a significant impact on its performance as a solar cell absorber. In this work, the structural, optical, and electronic properties of CdTe1-xSex films are examined for different Se concentrations. The band gap of this compound changes with composition with a minimum of 1.40 eV for x = 0.3. We show that with increasing x, the lattice constant of CdTe1-xSex decreases, which can influence the solubility of dopants. We find that alloying CdTe with Se changes the effect of Cu doping on the p-type conductivity in CdTe1-xSex, reducing the achievable charge carrier concentration with increasing x. Using a front surface CdTe1-xSex layer, compositional, structural and electronic grading is introduced to solar cells. The efficiency is increased, mostly due to an increase in the short-circuit current density caused by a combination of lower band gap and a better interface between the absorber and window layer, despite a loss in the open-circuit voltage caused by the lower band gap and reduced charge carrier concentration.
Recent advancements in CdTe photovoltaic efficiency have come from selenium grading, which reduces the band gap and significantly improves carrier lifetimes. In this work, density functional theory calculations were performed to understand the structural and electronic effects of Se alloying. Special quasirandom structures were used to simulate a random distribution of Se anions. Lattice parameters decrease linearly as Se concentration increases in line with Vegard's Law. The simulated band gap bowing shows strong agreement with experimental values. Selenium, by itself does not
“…Due to their remarkable optical and electrical properties, both compounds are extensively used in the manufacture of electronic devices. CdSe is a good light absorber which possesses excellent photoelectrical characteristics (Feng et al, 2010); therefore, it is used in the production of light emitting diodes (LEDs), photo-electronics, and transistors (Chate et al, 2013). The use of CdSe in the production of high efficiency hybrid solar cells has been investigated (Feng et al, 2010;Chate et al, 2013;Huynh et al, 2002).…”
Section: Introductionmentioning
confidence: 99%
“…CdSe is a good light absorber which possesses excellent photoelectrical characteristics (Feng et al, 2010); therefore, it is used in the production of light emitting diodes (LEDs), photo-electronics, and transistors (Chate et al, 2013). The use of CdSe in the production of high efficiency hybrid solar cells has been investigated (Feng et al, 2010;Chate et al, 2013;Huynh et al, 2002). Likewise, CdTe is used in the production of optoelectronic devices, gamma ray detectors (Bicknell et al, 1987), and laser windows (Punitha et al, 2015).…”
This work investigated the microbial toxicity of soluble species that can potentially be leached from the II–VI semiconductor materials, cadmium telluride and cadmium selenide. The soluble ions tested included: cadmium, selenite, selenate, tellurite, and tellurate. Their toxicity towards the acetoclastic and hydrogen-consuming trophic groups in a methanogenic consortium as well as towards a bioluminescent marine bacterium, Aliivibrio fischeri (Microtox® test), was assessed. The acetoclastic methanogenic activity was the most affected as evidenced by the low 50% inhibiting concentrations (IC50) values obtained of 8.6 mg L−1 for both cadmium and tellurite, 10.2 mg L−1 for tellurate, and 24.1 mg L−1 for selenite. Both tellurium oxyanions caused a strong inhibition of acetoclastic methanogenesis at low concentrations, each additional increment in concentration provided progressively less inhibition increase. In the case of the hydrogenotrophic methanogenesis, cadmium followed by selenite caused the greatest inhibition with IC50 values of 2.9 and 18.0 mg L−1, respectively. Tellurite caused a moderate effect as evidenced by a 36.8% inhibition of the methanogenic activity at the highest concentration tested, and a very mild effect of tellurate was observed. Microtox® analyses showed a noteworthy inhibition of cadmium, selenite, and tellurite with 50% loss in bioluminescence after 30 min of exposure of 5.5, 171.1, and 458.6 mg L−1, respectively. These results suggest that the leaching of cadmium, tellurium and selenium ions from semiconductor materials can potentially cause microbial toxicity.
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