{"id":220,"date":"2025-10-14T15:59:10","date_gmt":"2025-10-14T19:59:10","guid":{"rendered":"https:\/\/mse.ncsu.edu\/collazo\/?page_id=220"},"modified":"2025-10-14T16:31:52","modified_gmt":"2025-10-14T20:31:52","slug":"research","status":"publish","type":"page","link":"https:\/\/mse.ncsu.edu\/collazo\/research\/","title":{"rendered":"Research"},"content":{"rendered":"\n\n\n\n
\n \n
\n \n
\n
\n \n <\/svg>\n\n <\/span>\n

From Crystal to Device<\/h2>\n

\n Pioneering atomic-level insights\n <\/p>\n <\/div>\n <\/div>\n \n\n <\/div>\n\n\n

\n \n\n

We advance the science and technology of III-nitride and wide-bandgap semiconductor materials for optoelectronics, power devices and quantum systems. We aim to push the boundaries of crystal growth, polarity engineering, defect control and device integration, translating fundamental insights into practical photonic, UV and high-voltage applications.<\/p>\n\n\n <\/div>\n\n\n <\/div>\n \n\n\n

\n
\n \n
\n

Bulk and Epitaxial Growth of AlN\/GaN Crystals and Films<\/h2>\n

We develop scalable methods to grow high-purity aluminum nitride (AlN) and gallium nitride (GaN) crystals and epitaxial films with low defect densities, optimized doping and controlled texture. Our innovations include plasma-assisted MBE, MOCVD and bulk boule growth techniques. These materials form the foundation for advanced device architectures in UV light sources and power electronics.<\/p>\n <\/div>\n\n\n

\n\n
\"A<\/figure>\n\n<\/div>\n\n <\/div>\n <\/div>\n\n\n
\n
\n \n
\n

Polarity Engineering, Defect Control and Interface Design<\/h2>\n

Polarity (i.e. orientation of material crystal faces) plays a crucial role in device behavior. We manipulate polarity, strain and interfacial defects in heterostructures and lateral junctions to control carrier flow, reduce leakage and enhance performance. This thrust includes lateral homojunction devices, compositional grading and interface passivation strategies.<\/p>\n <\/div>\n\n\n

\n\n
\"Closeup<\/figure>\n\n<\/div>\n\n <\/div>\n <\/div>\n\n\n
\n
\n \n
\n

Device Integration, Characterization and Applications<\/h2>\n

We bridge materials with function by fabricating and testing devices such as UV LEDs, power diodes, deep-UV lasers and GaN transistors. Our characterization toolbox includes optical spectroscopy, high-resolution X-ray diffraction, electron microscopy, electrical transport and device testing under extreme conditions. We validate material advances in real-world device performance.<\/p>\n <\/div>\n\n\n

\n\n
\"\"<\/figure>\n\n<\/div>\n\n <\/div>\n <\/div>\n\n\n\n

Methods and Capabilities<\/h2>\n\n\n\n
    \n
  • Crystal growth and epitaxy<\/strong>: plasma-assisted MBE, MOCVD, bulk boule growth<\/li>\n\n\n\n
  • Structural and optical characterization<\/strong>: XRD, TEM, SEM, photoluminescence, cathodoluminescence<\/li>\n\n\n\n
  • Electrical and device testing<\/strong>: current-voltage, capacitance-voltage, high-voltage stress, UV emission measurement<\/li>\n\n\n\n
  • Polarity and interface engineering tools<\/strong>: wafer patterning, selective etching, atomic-scale analysis<\/li>\n<\/ul>\n\n\n\n

    Facilities and Equipment<\/h2>\n\n\n\n

    We maintain state-of-the-art infrastructure for wide-bandgap materials and devices, including:<\/p>\n\n\n\n

      \n
    • Epitaxial growth chambers (MBE, MOCVD)<\/li>\n\n\n\n
    • Bulk crystal furnaces and boule growth systems<\/li>\n\n\n\n
    • High-resolution TEM\/SEM and spectroscopy labs<\/li>\n\n\n\n
    • Electrical testing stations for high-voltage, UV and optoelectronic device characterization<\/li>\n<\/ul>\n\n\n
      \n \n
      \n \n
      \n
      \n
      \n
      \n

      Collaborations<\/h2>\n <\/div>\n
      \n \n\n \n
      \n
      \n \"Two\n <\/div>\n <\/div>\n \n
      \n \n

      HexaTech, Inc.<\/h3>\n \n\n \n\t \t

      Our lab partners with national labs, industry and university spin-out ventures. Notably, the commercial AlN crystal growth process pioneered in our group is licensed and commercialized by HexaTech, Inc.<\/strong> We also contribute to the UV lighting and power electronics ecosystem through collaborative projects, technology transfer, and startup development.<\/span>\n\t\t\t\n\t\t\t\n\t\t<\/svg><\/span><\/p>\n\t \t \n <\/div>\n\n <\/a>\n\n\n <\/div>\n <\/div>\n <\/div>\n<\/div>\n\n\n <\/div>\n\n\n

      \n \n
      \n
      \n

      “The world is energetically more and more hungry, and the importance of integrating all the sources of energy will become a big problem; and this is where aluminum nitrate-based technology comes in as a superstar.”<\/p>\n

      \n
      \n \"Zlatko\n <\/figure>\n
      \n \n

      Zlatko Sitar<\/p>\n \n

      Kobe Steel Distinguished Professor of Materials Science and Engineering
      Founder of Adroit Materials, Inc. and HexaTech, Inc.<\/p>\n <\/div>\n <\/div>\n <\/div>\n <\/blockquote>\n\n\n <\/div>\n\n\n <\/div>\n","protected":false},"excerpt":{"rendered":"

      Methods and Capabilities Facilities and Equipment We maintain state-of-the-art infrastructure for wide-bandgap materials and devices, including:<\/p>\n","protected":false},"author":536,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"views\/homepage.blade.php","meta":{"_acf_changed":false,"source":"","ncst_custom_author":"","ncst_show_custom_author":false,"ncst_dynamicHeaderBlockName":"ncst\/split-header","ncst_dynamicHeaderData":"{\"backgroundColor\":\"custombg_seven\",\"imageID\":136,\"imageURL\":\"https:\/\/mse.ncsu.edu\/collazo\/wp-content\/uploads\/sites\/8\/2025\/10\/wafer-scaled.jpeg\",\"useCTA\":false,\"boxPosition\":\"left\",\"ctaNum\":\"one\",\"imageAlt\":\"surface of Silicon Wafers and Microcircuits\"}","ncst_content_audit_freq":"","ncst_content_audit_date":"","ncst_content_audit_display":false,"ncst_backToTopFlag":"","footnotes":""},"class_list":["post-220","page","type-page","status-publish","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/mse.ncsu.edu\/collazo\/wp-json\/wp\/v2\/pages\/220","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mse.ncsu.edu\/collazo\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/mse.ncsu.edu\/collazo\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/mse.ncsu.edu\/collazo\/wp-json\/wp\/v2\/users\/536"}],"replies":[{"embeddable":true,"href":"https:\/\/mse.ncsu.edu\/collazo\/wp-json\/wp\/v2\/comments?post=220"}],"version-history":[{"count":3,"href":"https:\/\/mse.ncsu.edu\/collazo\/wp-json\/wp\/v2\/pages\/220\/revisions"}],"predecessor-version":[{"id":231,"href":"https:\/\/mse.ncsu.edu\/collazo\/wp-json\/wp\/v2\/pages\/220\/revisions\/231"}],"wp:attachment":[{"href":"https:\/\/mse.ncsu.edu\/collazo\/wp-json\/wp\/v2\/media?parent=220"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}