Z. Ju;X. Qi;S. Schaefer;M. R. McCartney;D. J. Smith;A. V. G. Chizmeshya;T. McCarthy;A. McMinn;S. Grover;Y.-H. Zhang
{"title":"利用分子束外延技术在晶格匹配的 InAs 基底上生长出锌斜长石和钨斜长石混合相的硒化镉","authors":"Z. Ju;X. Qi;S. Schaefer;M. R. McCartney;D. J. Smith;A. V. G. Chizmeshya;T. McCarthy;A. McMinn;S. Grover;Y.-H. Zhang","doi":"10.1109/JPHOTOV.2024.3417025","DOIUrl":null,"url":null,"abstract":"The II–VI compound semiconductor CdSe, which has both zincblende (ZB) and wurtzite (WZ) phases with bandgap energies of 1.67 and 1.74 eV, respectively, is an ideal candidate material for the top cell in a tandem solar cell with a Si bottom cell to achieve higher power conversion efficiency. In this work, molecular beam epitaxy growth of CdSe thin films on lattice-matched InAs(100) substrates reveals a single-phase ZB structure with high crystallinity and a low defect density. In contrast, all CdSe layers grown on InAs(111)B substrates have mixed ZB and WZ phases in coexistence, as confirmed by high-resolution X-ray diffraction, transmission electron microscopy (TEM), and photoluminescence (PL) measurements. The PL efficiencies of the CdSe layers grown on (111)B substrates are substantially lower than those grown on (100) substrates. This result is attributed to defects at the boundaries between the two different phases. Postgrowth annealing of CdSe layers grown on InAs(111)B at 250–450 °C converts most of the CdSe ZB material into the WZ phase, as evidenced by improved PL efficiency and TEM images. Density functional theory simulations confirm that the formation energy difference between the ZB and WZ phases for CdSe is very small compared with other conventional compound semiconductors, which is in good agreement with the experimental observations.","PeriodicalId":445,"journal":{"name":"IEEE Journal of Photovoltaics","volume":"14 5","pages":"752-757"},"PeriodicalIF":2.5000,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"CdSe With Mixed Zincblende and Wurtzite Phases Grown on Lattice-Matched InAs Substrates Using Molecular Beam Epitaxy\",\"authors\":\"Z. Ju;X. Qi;S. Schaefer;M. R. McCartney;D. J. Smith;A. V. G. Chizmeshya;T. McCarthy;A. McMinn;S. Grover;Y.-H. Zhang\",\"doi\":\"10.1109/JPHOTOV.2024.3417025\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The II–VI compound semiconductor CdSe, which has both zincblende (ZB) and wurtzite (WZ) phases with bandgap energies of 1.67 and 1.74 eV, respectively, is an ideal candidate material for the top cell in a tandem solar cell with a Si bottom cell to achieve higher power conversion efficiency. In this work, molecular beam epitaxy growth of CdSe thin films on lattice-matched InAs(100) substrates reveals a single-phase ZB structure with high crystallinity and a low defect density. In contrast, all CdSe layers grown on InAs(111)B substrates have mixed ZB and WZ phases in coexistence, as confirmed by high-resolution X-ray diffraction, transmission electron microscopy (TEM), and photoluminescence (PL) measurements. The PL efficiencies of the CdSe layers grown on (111)B substrates are substantially lower than those grown on (100) substrates. This result is attributed to defects at the boundaries between the two different phases. Postgrowth annealing of CdSe layers grown on InAs(111)B at 250–450 °C converts most of the CdSe ZB material into the WZ phase, as evidenced by improved PL efficiency and TEM images. Density functional theory simulations confirm that the formation energy difference between the ZB and WZ phases for CdSe is very small compared with other conventional compound semiconductors, which is in good agreement with the experimental observations.\",\"PeriodicalId\":445,\"journal\":{\"name\":\"IEEE Journal of Photovoltaics\",\"volume\":\"14 5\",\"pages\":\"752-757\"},\"PeriodicalIF\":2.5000,\"publicationDate\":\"2024-07-03\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"IEEE Journal of Photovoltaics\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://ieeexplore.ieee.org/document/10584072/\",\"RegionNum\":3,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"ENERGY & FUELS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"IEEE Journal of Photovoltaics","FirstCategoryId":"5","ListUrlMain":"https://ieeexplore.ieee.org/document/10584072/","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
CdSe With Mixed Zincblende and Wurtzite Phases Grown on Lattice-Matched InAs Substrates Using Molecular Beam Epitaxy
The II–VI compound semiconductor CdSe, which has both zincblende (ZB) and wurtzite (WZ) phases with bandgap energies of 1.67 and 1.74 eV, respectively, is an ideal candidate material for the top cell in a tandem solar cell with a Si bottom cell to achieve higher power conversion efficiency. In this work, molecular beam epitaxy growth of CdSe thin films on lattice-matched InAs(100) substrates reveals a single-phase ZB structure with high crystallinity and a low defect density. In contrast, all CdSe layers grown on InAs(111)B substrates have mixed ZB and WZ phases in coexistence, as confirmed by high-resolution X-ray diffraction, transmission electron microscopy (TEM), and photoluminescence (PL) measurements. The PL efficiencies of the CdSe layers grown on (111)B substrates are substantially lower than those grown on (100) substrates. This result is attributed to defects at the boundaries between the two different phases. Postgrowth annealing of CdSe layers grown on InAs(111)B at 250–450 °C converts most of the CdSe ZB material into the WZ phase, as evidenced by improved PL efficiency and TEM images. Density functional theory simulations confirm that the formation energy difference between the ZB and WZ phases for CdSe is very small compared with other conventional compound semiconductors, which is in good agreement with the experimental observations.
期刊介绍:
The IEEE Journal of Photovoltaics is a peer-reviewed, archival publication reporting original and significant research results that advance the field of photovoltaics (PV). The PV field is diverse in its science base ranging from semiconductor and PV device physics to optics and the materials sciences. The journal publishes articles that connect this science base to PV science and technology. The intent is to publish original research results that are of primary interest to the photovoltaic specialist. The scope of the IEEE J. Photovoltaics incorporates: fundamentals and new concepts of PV conversion, including those based on nanostructured materials, low-dimensional physics, multiple charge generation, up/down converters, thermophotovoltaics, hot-carrier effects, plasmonics, metamorphic materials, luminescent concentrators, and rectennas; Si-based PV, including new cell designs, crystalline and non-crystalline Si, passivation, characterization and Si crystal growth; polycrystalline, amorphous and crystalline thin-film solar cell materials, including PV structures and solar cells based on II-VI, chalcopyrite, Si and other thin film absorbers; III-V PV materials, heterostructures, multijunction devices and concentrator PV; optics for light trapping, reflection control and concentration; organic PV including polymer, hybrid and dye sensitized solar cells; space PV including cell materials and PV devices, defects and reliability, environmental effects and protective materials; PV modeling and characterization methods; and other aspects of PV, including modules, power conditioning, inverters, balance-of-systems components, monitoring, analyses and simulations, and supporting PV module standards and measurements. Tutorial and review papers on these subjects are also published and occasionally special issues are published to treat particular areas in more depth and breadth.