Critical Impurity Density in the Mott Metal-Insulator Transition, obtained in the n(p)-Type Degenerate

By basing on the same physical model and treatment method, as used in our recent works (Van Cong, 2024; 2023; 2023), we investigate the critical impurity density in the metal-insulator transition (MIT), obtained in the n(p)-type degenerate Si1−xGex- crystalline alloy, 0≤x≤1, and also applied to determine the optical band gap, being due to the effects of the size of donor (acceptor) d(a)-radius, rd(a), the x-Ge concentration, the temperature T, and finally the high d(a)-density, N, assuming that all the impurities are ionized even at T=0 K. In such the n(p)-type degenerate Si1−xGex- crystalline alloy, we will determine:  (i)-the critical impurity density &nbsp

(26.55 %, or 23.69 %)-Limiting Highest Efficiencies, obtained respectively in nn+(pp+) − pp(nn) Crystalline (XX ≡ CdTe, or CdSe)- Junction Solar Cells, Due to the Effects of Impurity Size, Temperature, Heavy Doping, and Photovoltaic Conversion

 In the n+(p+)−p(n) crystalline (X≡ CdTe or CdSe)-junction solar cells at 300K, due to the effects of impurity size, temperature, heavy doping, and photovoltaic conversion, we show that, with an increasing donor (acceptor)-radius rd(a), both the relative dielectric constant and photovoltaic conversion factor decrease, and the intrinsic band gap (IBG) increases, according to the increase in photovoltaic efficiency, as observed in Tables 1-5, being in good accordance with an important result obtained by Shockley and Queisser (1961), stating that for an increasing IBG the photovoltaic efficiency increases. Further, for highest values of rd(a), the limiting highest efficiencies are found to be given in Tables 4, 6, as: 26.55 %, and 23.69 %, obtained in such n+(p+)−p(n) crystalline (CdTe, or CdSe)-junction solar cells at the open circuit voltage Voc=0.82 V, and 0.89 V, respectively, and at T=300 K. Furthermore, from the well-known Carnot-efficiency theorem, as given in Eq. (46), being obtained from the second principle of the thermodynamics, and from the above results of limiting highest efficiencies, the corresponding highest hot reservoir temperatures, TH=408.4 K, and 393.1 K, respectively. Thus, as noted above, ηmax. and TH both increase with an increasing IBG, for each (X≡ CdTe, or CdSe)- crystal at T=300 K≡TC.&nbsp

Maximal Efficiencies in New Single Si 1-x Ge x- Alloy Junction Solar Cells at 300 K

In single n+(p+)−p(n) [X(x)≡Si1−xGex]-alloy junction solar cells at 300 K, 0≤x≤1, by basing on the same physical model and the same treatment method, as those used in our recent work (Van Cong et al., 2023; Van Cong, 2023), we will investigate the highest (or maximal) efficiencies, ηImax.(IImax.), obtained at the open circuit voltage Voc(=VocI(ocII)), according to highest hot reservoir temperatures TH(K), obtained from the Carnot efficiency theorem, being proved by entropy law, in the following. (i)-First, in the singl

Maximal Efficiencies in New Single GaAs 1−x Sb x-Alloy Junction Solar Cells at 300 K

In single n+(p+)−p(n) [X(x)≡GaAs1−xSbx]-alloy junction solar cells at 300 K, 0≤x≤1, by basing on the same physical model and the same treatment method, as those used in our recent work (Van Cong et al., 2023; Van Cong, 2023), we will investigate the highest (or maximal) efficiencies, ηImax.(IImax.), obtained at the open circuit voltage Voc(=VocI(ocII)), according to highest hot reservoir temperatures TH(K), obtained from the Carnot efficiency theorem, being proved by entropy law. Here, one first remarks that, with increasing x=(0, 0.5, 1), (i)- from Table 3, for the single n+−p X(x)-alloy junction solar cell and for given rSn(Cd)-radius, for example, ηImax.(↘)= 31.14%, 28.72%, 25.36%, according to TH(K)=435.7.420.9.401.9 Voc(V)=1.07 .1.07 1.09 1.17 espectively, while, (ii)- from Table 5, for the single p+−n X(x)-alloy junction solar cell and for given rCd(Sn)-radius, for example, ηIImax.(↗)= 33.04%, 34.26%, 35.47%, according to TH(K)=448.0,456.3

Maximal Efficiencies in New Single GaAs(1−x) P(x) - Alloy Junction Solar Cells at 300 K

In single n+(p+) − p(nn) [X(x) ≡ GA1−xPx]-alloy junction solar cells at 300 K, 0 ≤ xx ≤ 1, by basing on the same physical model and the same treatment method, as those used in our recent works (Van Cong, 2024), we will also investigate the highest (or maximal) efficiencies, ηImax .(IImax.) at the open circuit voltageVos(= Vos1 (os2 ),according to highest hot reservoir temperatures TH(K), obtained from the Carnot efficiency theorem, which was demonstrated by the use of the entropy law. Here, some concluding remarks are given in the following. (i)-First, with increasing x=(0, 0.5, 1), from Table 3, obtained for the single n+ − p X(x)-alloy junction solar cells, and for given rSn(Cd)-radius, for example, one obtains: ηImax (↗)= 31.18%, 33.495%, 35.99%, according to TH(K) = 435.9, 451.1, 468.7, at Vos (V) = 1.07, 1.06, 1.05, respectively. (ii)- Secondly, with increasing x=(0, 0.5, 1), from Table 5, obtained for the single p+ − n X(x)-alloy junction solar cells, and for given rCd(Sn)-radius, for example, one gets: ηηIImax (↘)= 33.05%, 31.95%, 31.37%, according to TH(K) = 448.0, 440.9, 437.1, at Vos (V)[>Vos(V)] = 1.20, 1.15, 1.12, respectively, suggesting that such ηImax .(IImax .)-and-TH variations dependon Vos(V)[> Vos (V)] − values. Then, in particular, as given in Table 3, for x = 0 and (rda ) =(pt), one gets: ηI =23.48 % and 29.76 % at Vos= 0.98 V and 1.1272 V, respectively, which can be compared with the corresponding results obtained by Moon et al. (2016) and Green et al. (2022) for the single-junction GaAs thin-film solar cell, 22.08 % and 29.71 %, with relative deviations in absolute values, 6.34 % and 0.17 %. Finally, one notes that, in order to obtain the highest efficiencies, the single GaAs1−x Px-alloy junction solar cells could be chosen rather than the single crystalline GaAs-junction solar cell

13.05% (14.82 %) – Limiting Highest Efficiencies Obtained Respectively in n+(p+)-p(n) Crystalline Ge-Junction Solar Cells at T=300 K, Due to the Effects of Impurity Size, Temperature, Heavy Doping, and Photovoltaic Conversion

In the n+(p+)−p(n) crystalline Ge-junction solar cells at 300K, due to the effects of impurity size, temperature, heavy doping, and photovoltaic conversion, we show that, with an increasing donor (acceptor)-radius rd(a), both the relative dielectric constant and photovoltaic conversion factor decrease, and the intrinsic band gap (IBG) increases, according to the increase in photovoltaic efficiency, as observed in Tables 1, 2 and 3, being in good accordance with an important result obtained by Shockley and Queisser (1961), with the use of the second law of thermodynamics, stating that for an increasing IBG the photovoltaic efficiency increases. Further, for highest values of rd(a), the limiting highest efficiencies are found to be given in Tables 2 and 3, as: 13.05 % (14.82 %), obtained in such n+(p+)−p(n) crystalline Ge-junction solar cells at 300 K, respectively. Then, from the well-known Carnot-efficiency theorem, as given in Eq. (47), being obtained by the second principle of thermodynamics, and from those limiting highest efficiencies, the corresponding highest hot reservoir temperatures, TH, are found to be given by: 345.04 K (352.20 K), respectively. In other words, TH also increases with an increasing IBG, being a new result.&nbsp

11.97% (12.12%)-Limiting Highest Efficiencies Obtained Respectively in nn+(pp+) − pp(nn) Crystalline GaSb Junction Solar Cells at T=300K, Due to the Effects of Impurity Size, Temperature, Heavy Doping, and Photovoltaic Conversion

In the n+(p+)−p(n) crystalline GaSb-junction solar cells at 300K, due to the effects of impurity size, temperature, heavy doping, and photovoltaic conversion, we show that, with an increasing donor (acceptor)-radius rd(a), both the relative dielectric constant and photovoltaic conversion factor decrease, and the intrinsic band gap increases, according to the increase in photovoltaic efficiency, as observed in Tables 1, 2 and 3, being in good accordance with an important result obtained by Shockley and Queisser (1961), with the use of the second law of thermodynamics, stating that for an increasing intrinsic band gap the photovoltaic efficiency increases. Further, for highest values of rd(a), the limiting highest efficiencies are found to be given in Tables 2 and 3, as: 11.97 % (12.12 %), obtained in such n+(p+)−p(n) crystalline GaSb-junction solar cells at 300 K, respectively.&nbsp

(43.82 %, or 44.05 %)-Limiting Highest Efficiencies, Obtained Respectively in nn+(pp+) − pp(nn) Crystalline CdS-Junction Solar Cells at T=300 K, Due to the Effects of Impurity Size, Temperature, Heavy Doping, and Photovoltaic Conversion

In the n+(p+)-p(n) crystalline (SdS) junction solar cells at 300K, due to the effects of impurity size, temperature, heavy doping, and photovoltaic conversion, we show that, with an increasing donor (acceptor)-radius rd(a) both the relative dielectric constant and photovoltaic conversion factor decrease, and the intrinsic band gap (IBG) increases, according to the increase in photovoltaic efficiency n, as observed in Tables 1-3. This is found to be in good accordance with an important result obtained by Shockley and Queisser (1961), stating that, for a fixed fraction of the total radiative recombination (=1) and for an increasing IBG (0<IBG(eV) ≤1.1), n increases and its maximum value is equal to 30 % at IBG=1.1eV.  Further, for highest values of rd(a) the limiting highest efficiencies are found to be given in Tables 2 and 3, as: 43.82 %, and 44.05 %, obtained in such n+(p+)-p(n) crystalline CdS-junction solar cells at T=300 K, with a large value of IBG (2.395 eV ≤IBG≤ 2.462eV, as seen in Table 1) and at the open circuit voltage Voc=2.7V. Furthermore, from the well-known Carnot-efficiency theorem, as given in Eq. (46), being obtained from the second principle of thermodynamics, and from the above results of limiting highest efficiencies, the corresponding highest hot reservoir temperatures, TH =534K and 536 K, respectively. Thus, as noted above, both nmax and TH increase with an increasing IBG, and at T=300 K=TC

Characteristics of integrated mangrove-shrimp farming systems in Ben Tre Province, Vietnam: preliminary findings for organic shrimp production certification

Mangrove forests play a critical role in natural disaster resistance and provide meaningful livelihoods for localcommunities, especially integrated mangrove shrimp farming (IMSF) systems. Organic shrimp certification actuallyincreases the value chains of shrimp farming in addition to ameliorating mangrove–forest management. Identifyingtechnical issues and assessing environmental risks are the leading concerns when considering organic shrimpproduction certification. In this study, the technical practices of 30 households were investigated, and surface waterand sediment samples were collected in the IMSF models and adjacent rivers in the Thua Duc Forest ManagementBoard area, Ben Tre Province. Data collected from shrimp farming ponds and the environmental backgroundwere referred to both the Naturland and National Standards. The results showed that the average mangroveforest and shrimp pond ratio was 56.90:42.70 (%). Two technical issues were highlighted: (i) the use of rotenone,known as a toxin to kill undesirable fish before stocking shrimp, and (ii) annual shrimp pond regeneration causingincreased pollution. The data showed that higher concentrations of TSS and P-PO43- were detected in surroundingrivers, while surface water in either IMSF ponds or adjacent rivers slightly surpassed the permissible levels oftotal Fe concentration. All parameters—including heavy metals; toxic and persistent parameters; oil and greaseand coliforms analysed in surface water, and sediment samples—were lower than the detection and permissiblelevels. The results provided evidence that the IMSF’s practices and environmental characteristics were suitable forrecommending the Naturland Standards. Recommendations and technical interventions for farmers are necessaryto help reduce Fe levels and the safe use of rotenone in IMSF systems. An environmental quality monitoringprogramme at the target area should be applied when launching organic shrimp production

Whole-genome sequencing of three local rice varieties (Oryza sativa L.) in Vietnam

Recently, a new technology, Next-generation sequencing (NGS) has been launched and providing whole-genome sequences that helps identify molecular markers across the genome. DNA markers such as single nucleotides and insertion – deletion (InDel) polymorphisms were widely used for plant breeding particularly to distinguish important traits in rice. These PCR-based markers can be used for the precision detection of polymorphisms. Moreover, PCR-based approaches are simple and effective methods for dealing with the issue of fraudulent labeling and adulteration in the global rice industry. In this study, three local varieties of Oryza sativa L. in Vietnam were sequenced with up to ten times genome depth and at least four times coverage (~83%) using the Illumina HiSeq2000™ system, with an average of 6.5 GB clean data per sample, generated after filtering low-quality data. The data was approximately mapped up to 95% to the reference genome IRGSP 1.0. The results obtained from this study will contribute to a wide range of valuable information for further investigation into this germplasm