Pub Date : 2023-04-01DOI: 10.15251/jor.2023.192.231
P. Kirthika, N. Thangaraj, P. Anitha
The Nickel Manganese Tungsten (Ni-Mn-W) thin films were prepared at different temperature and time of deposition on copper substrate. The crystal structure and morphology of deposits were analysed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD revealed that the structure of Ni-Mn-W thin films with have an average grain size of about 28 nm for 45o C. The elemental analysis of Ni-Mn-W thin films were obtained by energy dispersive X-ray spectroscopy (EDAX). The magnetic properties of electrodeposited Ni-Mn-W thin films were obtained by vibrating sample magnetometer (VSM). The magnetic parameters of Ni-Mn-W films such as coercivity and saturation magnetization were decreased with increasing of grain size. The hardness of the films was studies by Vicker Hardness tester through diamond intender method.
{"title":"Influence of bath temperature and deposition time on hardness and magnetisation of electrodeposited Nickel Manganese Tungsten thin films","authors":"P. Kirthika, N. Thangaraj, P. Anitha","doi":"10.15251/jor.2023.192.231","DOIUrl":"https://doi.org/10.15251/jor.2023.192.231","url":null,"abstract":"The Nickel Manganese Tungsten (Ni-Mn-W) thin films were prepared at different temperature and time of deposition on copper substrate. The crystal structure and morphology of deposits were analysed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD revealed that the structure of Ni-Mn-W thin films with have an average grain size of about 28 nm for 45o C. The elemental analysis of Ni-Mn-W thin films were obtained by energy dispersive X-ray spectroscopy (EDAX). The magnetic properties of electrodeposited Ni-Mn-W thin films were obtained by vibrating sample magnetometer (VSM). The magnetic parameters of Ni-Mn-W films such as coercivity and saturation magnetization were decreased with increasing of grain size. The hardness of the films was studies by Vicker Hardness tester through diamond intender method.","PeriodicalId":54394,"journal":{"name":"Journal of Ovonic Research","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41646200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.15251/jor.2023.192.207
E. Obot, C. Augustine, R. Chikwenze, S. Amadi, P. Okpani, P. Kalu, B. J. Robert, O. Nwoke, A.E. Igweoke, R. O. Okoro
This contribution presents structural, optical and electrical properties of PbS/CdS thin films at different annealing temperatures. The XRD analysis reveal the existence of three different crystalline phases, i.e., the beta-CdS, hawleyite-CdS and greenockite-alpha-CdS phases within the CdS-shell of PbS/CdS core shell thin film. The dislocation density and microstrain decreased with annealing temperatures indicating a decrease in lattice imperfections and formation of high quality film and it can be attributed to the increase in grain size of the film with increase in annealing temperatures. Optical studies placed the band gaps at 1.25eV-1.75eV. About the same magnitude were found from electrical conductivity test. The samples exhibited high conductivity with increasing annealing temperatures which resulted to the bumping of electrons from the valence band to the conduction band. The high absorbance suggest that the film could be coated on collectors to enhance solar energy collection. The achieved band gaps placed the PbS/CdS fabricated with the presented method as a good material for solar photovoltaic applications.
{"title":"Structural, optical and electrical properties of sulphide based heterojunction thin film","authors":"E. Obot, C. Augustine, R. Chikwenze, S. Amadi, P. Okpani, P. Kalu, B. J. Robert, O. Nwoke, A.E. Igweoke, R. O. Okoro","doi":"10.15251/jor.2023.192.207","DOIUrl":"https://doi.org/10.15251/jor.2023.192.207","url":null,"abstract":"This contribution presents structural, optical and electrical properties of PbS/CdS thin films at different annealing temperatures. The XRD analysis reveal the existence of three different crystalline phases, i.e., the beta-CdS, hawleyite-CdS and greenockite-alpha-CdS phases within the CdS-shell of PbS/CdS core shell thin film. The dislocation density and microstrain decreased with annealing temperatures indicating a decrease in lattice imperfections and formation of high quality film and it can be attributed to the increase in grain size of the film with increase in annealing temperatures. Optical studies placed the band gaps at 1.25eV-1.75eV. About the same magnitude were found from electrical conductivity test. The samples exhibited high conductivity with increasing annealing temperatures which resulted to the bumping of electrons from the valence band to the conduction band. The high absorbance suggest that the film could be coated on collectors to enhance solar energy collection. The achieved band gaps placed the PbS/CdS fabricated with the presented method as a good material for solar photovoltaic applications.","PeriodicalId":54394,"journal":{"name":"Journal of Ovonic Research","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49082069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.15251/jor.2023.192.153
M. A. Abdulsattar, M. Hussein, M. Kahaly
In the present work, a density functional theory (DFT) calculation to simulate reduced graphene oxide (rGO) hybrid with zinc oxide (ZnO) nanoparticle's sensitivity to NO2 gas is performed. In comparison with the experiment, DFT calculations give acceptable results to available bond lengths, lattice parameters, X-ray photoelectron spectroscopy (XPS), energy gaps, Gibbs free energy, enthalpy, entropy, etc. to ZnO, rGO, and ZnO/rGO hybrid. ZnO and rGO show n-type and p-type semiconductor behavior, respectively. The formed p-n heterojunction between rGO and ZnO is of the staggering gap type. Results show that rGO increases the sensitivity of ZnO to NO2 gas as they form a hybrid. ZnO/rGO hybrid has a higher number of vacancies that can be used to attract oxygen atoms from NO2 and change the resistivity of the hybrid. The combined reduction of oxygen from NO2 and NO can give a very high value of the Gibbs free energy of reaction that explains the ppb level sensitivity of the ZnO/rGO hybrid. The dissociation of NO2 in the air reduces the sensitivity of the ZnO/rGO hybrid at temperatures higher than 300 ̊C.
{"title":"Effect of reduced graphene oxide hybridization on ZnO nanoparticles sensitivity to NO2 gas: A DFT study","authors":"M. A. Abdulsattar, M. Hussein, M. Kahaly","doi":"10.15251/jor.2023.192.153","DOIUrl":"https://doi.org/10.15251/jor.2023.192.153","url":null,"abstract":"In the present work, a density functional theory (DFT) calculation to simulate reduced graphene oxide (rGO) hybrid with zinc oxide (ZnO) nanoparticle's sensitivity to NO2 gas is performed. In comparison with the experiment, DFT calculations give acceptable results to available bond lengths, lattice parameters, X-ray photoelectron spectroscopy (XPS), energy gaps, Gibbs free energy, enthalpy, entropy, etc. to ZnO, rGO, and ZnO/rGO hybrid. ZnO and rGO show n-type and p-type semiconductor behavior, respectively. The formed p-n heterojunction between rGO and ZnO is of the staggering gap type. Results show that rGO increases the sensitivity of ZnO to NO2 gas as they form a hybrid. ZnO/rGO hybrid has a higher number of vacancies that can be used to attract oxygen atoms from NO2 and change the resistivity of the hybrid. The combined reduction of oxygen from NO2 and NO can give a very high value of the Gibbs free energy of reaction that explains the ppb level sensitivity of the ZnO/rGO hybrid. The dissociation of NO2 in the air reduces the sensitivity of the ZnO/rGO hybrid at temperatures higher than 300 ̊C.","PeriodicalId":54394,"journal":{"name":"Journal of Ovonic Research","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43398748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.15251/jor.2023.192.165
L. Ayat, A. Idda
In this paper we present the results of the numerical simulation using wx-AMPS1D software of a solar cell based on hydrogenated amorphous silicon (a-Si: H / c-SiGe), the top layer has the largest band gap, while the bottom layer has the smallest bandgap. This design allows less energetic photons to pass through the upper layer(s) and be absorbed by the layer below, which increases the overall efficiency of the solar cell to obtain an efficiency high conversion rate. As the results, remarkable improvements on Voc, Jsc and FF have been achieved with the incorporation of n-c-SiGe layer, we achieved an efficiency of 11.93%.
本文利用wx-AMPS1D软件对氢化非晶硅(a- si: H / c-SiGe)太阳能电池进行了数值模拟，结果表明，顶层的带隙最大，底层的带隙最小。这种设计允许较少能量的光子通过上层并被下层吸收，从而提高了太阳能电池的整体效率，从而获得高效率的高转换率。结果表明，n-c-SiGe层的加入对Voc、Jsc和FF都有显著的改善，效率达到11.93%。
{"title":"Analysis of a-Si:H/SiGe heterostructure solar cell","authors":"L. Ayat, A. Idda","doi":"10.15251/jor.2023.192.165","DOIUrl":"https://doi.org/10.15251/jor.2023.192.165","url":null,"abstract":"In this paper we present the results of the numerical simulation using wx-AMPS1D software of a solar cell based on hydrogenated amorphous silicon (a-Si: H / c-SiGe), the top layer has the largest band gap, while the bottom layer has the smallest bandgap. This design allows less energetic photons to pass through the upper layer(s) and be absorbed by the layer below, which increases the overall efficiency of the solar cell to obtain an efficiency high conversion rate. As the results, remarkable improvements on Voc, Jsc and FF have been achieved with the incorporation of n-c-SiGe layer, we achieved an efficiency of 11.93%.","PeriodicalId":54394,"journal":{"name":"Journal of Ovonic Research","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42761407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.15251/jor.2023.192.187
R. I. Jasim, E. H. Hadi, S. Chiad, N. Habubi, M. Jadan, J. Addasi
Using thermal evaporation, thin films of silver-doped CdSe were synthesized on glass bases. A hexagonal structure with a preference orientation along (100) plane according to the X-ray diffraction pattern. The surface topography was determined using Atomic Force Microscopy (AFM). AFM detects spherical nature nanoparticles and roughness rate of the CdSe thin film decreases and the root mean square decreases with (2 and 4) % doping in silver. As the doping content increase, the optical energy bandgap decrease from 1.85 eV to 1.75 eV. Optical analysis indicates that Ag doping in CdSe results in a redshift in band edge.
{"title":"Effect of silver-doping on the structural, topography and optical CdSe thin films","authors":"R. I. Jasim, E. H. Hadi, S. Chiad, N. Habubi, M. Jadan, J. Addasi","doi":"10.15251/jor.2023.192.187","DOIUrl":"https://doi.org/10.15251/jor.2023.192.187","url":null,"abstract":"Using thermal evaporation, thin films of silver-doped CdSe were synthesized on glass bases. A hexagonal structure with a preference orientation along (100) plane according to the X-ray diffraction pattern. The surface topography was determined using Atomic Force Microscopy (AFM). AFM detects spherical nature nanoparticles and roughness rate of the CdSe thin film decreases and the root mean square decreases with (2 and 4) % doping in silver. As the doping content increase, the optical energy bandgap decrease from 1.85 eV to 1.75 eV. Optical analysis indicates that Ag doping in CdSe results in a redshift in band edge.","PeriodicalId":54394,"journal":{"name":"Journal of Ovonic Research","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45077678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.15251/jor.2023.192.175
B. M. Alotaibi, H. Al-Yousef, A. Atta, F. Taher
Different contents of manganese oxide (MnO2) and zinc oxide (ZnO) were combined with polyvinyl alcohol (PVA) to form flexi MnO2/PVA as well as ZnO/PVA nanocomposite films. XRD as well SEM methodologies are used to evaluate the properties of the fabricated films. The XRD analysis demonstrates that MnO2/PVA as well as ZnO/PVA composites were effectively fabricated. The SEM pictures show that MnO2 and ZnO are uniformly dispersed throughout the PVA polymeric chains. Furthermore, the electrical conductivities, dielectric permittivity, electric moduli behaviors, as well as dielectric impedances of PVA, MnO2/PVA, ZnO/PVA films were recorded using LCR method in frequencies 102 to 106 Hz. At 105 Hz, the dielectric enhanced from 2.05 for PVA to 5.5 on PVA/5%ZnO and 4.15 for PVA/10%MnO2, while the conductivities increase from 1.05x10-7 S/cm for PVA to 4.01x10-7 S/cm for PVA/5%ZnO and to 5.4x10-7 S/cm for PVA/10%MnO2. The current work pave the way to using of ZnO/PVA and MnO2/PVA flexi nanocomposite films in a different uses including battery, super-capacitors, as well as storage devices.
{"title":"Effects of inorganic MnO2 and ZnO nanofillers on the structural investigations and dielectric behaviour of PVA polymeric materials","authors":"B. M. Alotaibi, H. Al-Yousef, A. Atta, F. Taher","doi":"10.15251/jor.2023.192.175","DOIUrl":"https://doi.org/10.15251/jor.2023.192.175","url":null,"abstract":"Different contents of manganese oxide (MnO2) and zinc oxide (ZnO) were combined with polyvinyl alcohol (PVA) to form flexi MnO2/PVA as well as ZnO/PVA nanocomposite films. XRD as well SEM methodologies are used to evaluate the properties of the fabricated films. The XRD analysis demonstrates that MnO2/PVA as well as ZnO/PVA composites were effectively fabricated. The SEM pictures show that MnO2 and ZnO are uniformly dispersed throughout the PVA polymeric chains. Furthermore, the electrical conductivities, dielectric permittivity, electric moduli behaviors, as well as dielectric impedances of PVA, MnO2/PVA, ZnO/PVA films were recorded using LCR method in frequencies 102 to 106 Hz. At 105 Hz, the dielectric enhanced from 2.05 for PVA to 5.5 on PVA/5%ZnO and 4.15 for PVA/10%MnO2, while the conductivities increase from 1.05x10-7 S/cm for PVA to 4.01x10-7 S/cm for PVA/5%ZnO and to 5.4x10-7 S/cm for PVA/10%MnO2. The current work pave the way to using of ZnO/PVA and MnO2/PVA flexi nanocomposite films in a different uses including battery, super-capacitors, as well as storage devices.","PeriodicalId":54394,"journal":{"name":"Journal of Ovonic Research","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43583318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.15251/jor.2023.192.141
K. I. Hussein, M. Alqahtani, A. Almarhaby, R. S. Alayyash, E. Elshiekh
In numerous tissue engineering and dental applications, bioactive glasses are utilized. These glasses have unique characteristics that make them attractive candidates for a variety of applications. A new bioactive glass system with the structure of 45P2O5 − 20CaO − 15CaCL2 − 8KF − (10 − x) Li2O − (x) TiO2 was developed in this study, with x = 2, 6, and 8 mol%. For usage in radiation protective applications, it was evaluated. By using an ultraviolet–visible spectrophotometer, we were able to measure the absorbance (Abs) and transmittance (T %) in the range of wavelengths 190–2500 nm. Furthermore, the optical energy gap of the produced glasses was determined. Using the MIKE software, the mass attenuation coefficients (MAC) of the bioactive glasses under investigation were calculated for energies ranging from 15 to 200 keV. The 𝐿𝐿𝐿𝐿𝐿𝐿, 𝑍𝑍𝑒𝑒𝑒𝑒𝑒𝑒, 𝑁𝑁𝑒𝑒𝑒𝑒𝑒𝑒, 𝐻𝐻𝐻𝐻𝐻𝐻, 𝑇𝑇𝑇𝑇𝑇𝑇, 𝑎𝑎𝑎𝑎𝑎𝑎 𝑀𝑀𝑀𝑀𝑀𝑀 (Linear attenuation coefficient, effective atomic number, effective electron density, half value layer, tenth value layer, and mean free path) of the bioactive glasses were calculated. According to the findings, the addition of titanium dioxide (TiO2) as well as the metal oxide such as Li2O to bioactive glasses generates significant differences in the attenuation characteristics of bioactive glasses. The results indicate that the PCKLT3( 𝑇𝑇𝑇𝑇𝑇𝑇2= 8mol%) bioactive-glass sample had the best attenuation among other samples.
{"title":"Correlation between optical and shielding properties of phosphate glasses with alkaline oxide and their application","authors":"K. I. Hussein, M. Alqahtani, A. Almarhaby, R. S. Alayyash, E. Elshiekh","doi":"10.15251/jor.2023.192.141","DOIUrl":"https://doi.org/10.15251/jor.2023.192.141","url":null,"abstract":"In numerous tissue engineering and dental applications, bioactive glasses are utilized. These glasses have unique characteristics that make them attractive candidates for a variety of applications. A new bioactive glass system with the structure of 45P2O5 − 20CaO − 15CaCL2 − 8KF − (10 − x) Li2O − (x) TiO2 was developed in this study, with x = 2, 6, and 8 mol%. For usage in radiation protective applications, it was evaluated. By using an ultraviolet–visible spectrophotometer, we were able to measure the absorbance (Abs) and transmittance (T %) in the range of wavelengths 190–2500 nm. Furthermore, the optical energy gap of the produced glasses was determined. Using the MIKE software, the mass attenuation coefficients (MAC) of the bioactive glasses under investigation were calculated for energies ranging from 15 to 200 keV. The 𝐿𝐿𝐿𝐿𝐿𝐿, 𝑍𝑍𝑒𝑒𝑒𝑒𝑒𝑒, 𝑁𝑁𝑒𝑒𝑒𝑒𝑒𝑒, 𝐻𝐻𝐻𝐻𝐻𝐻, 𝑇𝑇𝑇𝑇𝑇𝑇, 𝑎𝑎𝑎𝑎𝑎𝑎 𝑀𝑀𝑀𝑀𝑀𝑀 (Linear attenuation coefficient, effective atomic number, effective electron density, half value layer, tenth value layer, and mean free path) of the bioactive glasses were calculated. According to the findings, the addition of titanium dioxide (TiO2) as well as the metal oxide such as Li2O to bioactive glasses generates significant differences in the attenuation characteristics of bioactive glasses. The results indicate that the PCKLT3( 𝑇𝑇𝑇𝑇𝑇𝑇2= 8mol%) bioactive-glass sample had the best attenuation among other samples.","PeriodicalId":54394,"journal":{"name":"Journal of Ovonic Research","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43483987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-01DOI: 10.15251/jor.2023.192.197
C. Zaouche, L. Dahbi, S. Benramache, A. Harouache, Y. Derouiche, M. Kharroubi, H. A. Haslouk, M. A. A. Banalhag, H. M. Alkhojah
The effect of Ni doping on structural, optical and electrical properties of deposited Zn1-xNixO thin films on glass substrate by spray pyrolysis technique has been studied. The main objective of this research is to study the change of the physical and optical properties of Zn1-xNixO thin films that are fabricant to semiconductor with different doping levels x. These levels are 0 at.%, 2 at.%, 4 at.%, 8 at.% and 12 at.%. The transmission spectra show that the Zn1-xNixO thin films have a good optical transparency in the visible region from 88 to 95%. The optical gap energy of the Zn1-xNixO thin films varied between 3.25 and 3.35 eV. The urbach energy varied between 65 and 230 meV. However, the Zn0.88Ni0.12O thin films have many defects with maximum value of urbach energy. The Zn0.88Ni0.12O thin films have minimum value of optical gap energy. The Zn0.88Ni0.12O thin films have maximum value of the electrical conductivity which is 9.40 (Ω.cm)-1 . The average electrical conductivity of our films is about (7.52 (Ω.cm)-1 ). XRD patterns of the Zn1- xNixO thin films indicate that films are polycrystalline with hexagonal wurtzite structure.
{"title":"Study the effect of Ni doping on structural, optical and electrical properties of Zn1-xNixO thin films deposited by spray pyrolysis technique","authors":"C. Zaouche, L. Dahbi, S. Benramache, A. Harouache, Y. Derouiche, M. Kharroubi, H. A. Haslouk, M. A. A. Banalhag, H. M. Alkhojah","doi":"10.15251/jor.2023.192.197","DOIUrl":"https://doi.org/10.15251/jor.2023.192.197","url":null,"abstract":"The effect of Ni doping on structural, optical and electrical properties of deposited Zn1-xNixO thin films on glass substrate by spray pyrolysis technique has been studied. The main objective of this research is to study the change of the physical and optical properties of Zn1-xNixO thin films that are fabricant to semiconductor with different doping levels x. These levels are 0 at.%, 2 at.%, 4 at.%, 8 at.% and 12 at.%. The transmission spectra show that the Zn1-xNixO thin films have a good optical transparency in the visible region from 88 to 95%. The optical gap energy of the Zn1-xNixO thin films varied between 3.25 and 3.35 eV. The urbach energy varied between 65 and 230 meV. However, the Zn0.88Ni0.12O thin films have many defects with maximum value of urbach energy. The Zn0.88Ni0.12O thin films have minimum value of optical gap energy. The Zn0.88Ni0.12O thin films have maximum value of the electrical conductivity which is 9.40 (Ω.cm)-1 . The average electrical conductivity of our films is about (7.52 (Ω.cm)-1 ). XRD patterns of the Zn1- xNixO thin films indicate that films are polycrystalline with hexagonal wurtzite structure.","PeriodicalId":54394,"journal":{"name":"Journal of Ovonic Research","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43923269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-20DOI: 10.15251/jor.2023.191.81
M. Gassoumi, A. Helali, Z. Elleuch, N. Boughdiri, H. Guesmi, S. Rejab, H. Maaref
When the AlGaN/GaN high electron mobility transistor (HEMT) is strongly biased, the speed of the electrons in the channel increases, which leads to an injection of electrons into the buffer, and consequently the appearance of the "short channel effect" phenomenon, which limits the performance of the component to overcome this effect and increase the power/frequency performance of the component, one solution consists in using a confinement barrier. This involves placing an electrostatic barrier under the GaN channel so as to block the injection of electrons into the buffer layer when the transistor is highly biased, and a BGaN confinement barrier because this semiconductor has very interesting physical properties, as well as better electrical isolation between the well and the substrate thanks to the optimization of the buffer. In this paper, the main objective is to study the effect of adding BGaN confinement barrier and its influence on transistor performance.
{"title":"Electron confinement enhancement in AlGaN/AlN/GaN HEMT using BGaN buffer","authors":"M. Gassoumi, A. Helali, Z. Elleuch, N. Boughdiri, H. Guesmi, S. Rejab, H. Maaref","doi":"10.15251/jor.2023.191.81","DOIUrl":"https://doi.org/10.15251/jor.2023.191.81","url":null,"abstract":"When the AlGaN/GaN high electron mobility transistor (HEMT) is strongly biased, the speed of the electrons in the channel increases, which leads to an injection of electrons into the buffer, and consequently the appearance of the \"short channel effect\" phenomenon, which limits the performance of the component to overcome this effect and increase the power/frequency performance of the component, one solution consists in using a confinement barrier. This involves placing an electrostatic barrier under the GaN channel so as to block the injection of electrons into the buffer layer when the transistor is highly biased, and a BGaN confinement barrier because this semiconductor has very interesting physical properties, as well as better electrical isolation between the well and the substrate thanks to the optimization of the buffer. In this paper, the main objective is to study the effect of adding BGaN confinement barrier and its influence on transistor performance.","PeriodicalId":54394,"journal":{"name":"Journal of Ovonic Research","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41504431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-20DOI: 10.15251/jor.2023.191.87
M. Velliangiri, M. Karthikeyan, G. Sureshkannan
Powder metallurgy has made it easier to develop Ultra high Al-Gr (5 wt% Gr) composite materials for commercial solar thermal collectors. This work seeks an optimum aluminumgraphene composite with superior thermo-mechanical properties for the thermal collector. Experimentally found that an AMMC matrix with 1.0 wt% of Gr has 282 W/mK thermal conductivity, 129 percent developed than Al (123 W/mK), and also found Al+Gr has a lower thermal expansion coefficient than pure Al. Predicted different composite densities and focused to retain 96.5 percent of aluminum density after sintering. Investigated analytical techniques and included some investigation like Raman spectroscopy, X-ray diffraction, FESM, and electricity-dispersive X-ray grain size and property and also identified high-quality composites and predicted their homogeneity and invulnerability. Predicted suitable Sintering temperature was 626 degrees Celsius which increased from 300 degrees Celsius. Energy and thermal conductivity were found that increases with increasing temperature and compared to pure Al. According to this investigation, when increased the graphene weight percentage proportion from 0 to 5.0 wt%. Results show that conductivity increases from 210 to 412 W/mK and mechanical characteristics slightly drop from 16 to 19% as pH rises from 5 to 5.5. Based on this investigation Al+Gr composites may be used for solar thermal collectors and heat sinks and also appropriate ultra-high Al+5.5 wt% suitable for solar collectors.
{"title":"The development of ultra-high aluminium graphene metal matrix composites (MMC) and improved the thermo-mechanical properties","authors":"M. Velliangiri, M. Karthikeyan, G. Sureshkannan","doi":"10.15251/jor.2023.191.87","DOIUrl":"https://doi.org/10.15251/jor.2023.191.87","url":null,"abstract":"Powder metallurgy has made it easier to develop Ultra high Al-Gr (5 wt% Gr) composite materials for commercial solar thermal collectors. This work seeks an optimum aluminumgraphene composite with superior thermo-mechanical properties for the thermal collector. Experimentally found that an AMMC matrix with 1.0 wt% of Gr has 282 W/mK thermal conductivity, 129 percent developed than Al (123 W/mK), and also found Al+Gr has a lower thermal expansion coefficient than pure Al. Predicted different composite densities and focused to retain 96.5 percent of aluminum density after sintering. Investigated analytical techniques and included some investigation like Raman spectroscopy, X-ray diffraction, FESM, and electricity-dispersive X-ray grain size and property and also identified high-quality composites and predicted their homogeneity and invulnerability. Predicted suitable Sintering temperature was 626 degrees Celsius which increased from 300 degrees Celsius. Energy and thermal conductivity were found that increases with increasing temperature and compared to pure Al. According to this investigation, when increased the graphene weight percentage proportion from 0 to 5.0 wt%. Results show that conductivity increases from 210 to 412 W/mK and mechanical characteristics slightly drop from 16 to 19% as pH rises from 5 to 5.5. Based on this investigation Al+Gr composites may be used for solar thermal collectors and heat sinks and also appropriate ultra-high Al+5.5 wt% suitable for solar collectors.","PeriodicalId":54394,"journal":{"name":"Journal of Ovonic Research","volume":" ","pages":""},"PeriodicalIF":1.0,"publicationDate":"2023-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46807989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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