{"title":"First-principles analysis of the optoelectronic properties of defective gallium nitride (Conference Presentation)","authors":"S. Sharifzadeh","doi":"10.1117/12.2514852","DOIUrl":null,"url":null,"abstract":"III-Nitrides form a class of wide bandgap semiconductors that have broad applications in optoelectronics technology due to their relatively large band gap, high carrier drift velocity and high breakdown voltage. In particular, GaN and its alloys are promising as component materials in solid-state lighting, radio-frequency, and power electronics. However, these materials generally grow with high defect densities, which can substantially degrade their electronic and optical properties. Therefore, an accurate and detailed knowledge of the influence of defects on their electronic structure will be central to the design of new high-performance materials. Here, we take a density functional theory (DFT) and many-body perturbation theory (MBPT) approach to describe the excited-states of defective GaN. Utilizing MBPT within the GW/BSE approximation, we develop an approach to systematically identify defects, and their associated trap state energies. For a +1 charged nitrogen vacancy within bulk GaN, the predicted bandstructure indicates that this particular defect results in the formation of shallow defect states with trap state energies near the band edges. However, analysis of the electron-hole correlation function reveals that the low-energy excitations are comprised of a mixed bulk-like and defect-like character with significant exciton binding energies (~ 0.1 eV). We discuss the implications of these defect-induced-states for the electron transport and optical properties of GaN.","PeriodicalId":249147,"journal":{"name":"Physics and Simulation of Optoelectronic Devices XXVII","volume":"11 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2019-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physics and Simulation of Optoelectronic Devices XXVII","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1117/12.2514852","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
III-Nitrides form a class of wide bandgap semiconductors that have broad applications in optoelectronics technology due to their relatively large band gap, high carrier drift velocity and high breakdown voltage. In particular, GaN and its alloys are promising as component materials in solid-state lighting, radio-frequency, and power electronics. However, these materials generally grow with high defect densities, which can substantially degrade their electronic and optical properties. Therefore, an accurate and detailed knowledge of the influence of defects on their electronic structure will be central to the design of new high-performance materials. Here, we take a density functional theory (DFT) and many-body perturbation theory (MBPT) approach to describe the excited-states of defective GaN. Utilizing MBPT within the GW/BSE approximation, we develop an approach to systematically identify defects, and their associated trap state energies. For a +1 charged nitrogen vacancy within bulk GaN, the predicted bandstructure indicates that this particular defect results in the formation of shallow defect states with trap state energies near the band edges. However, analysis of the electron-hole correlation function reveals that the low-energy excitations are comprised of a mixed bulk-like and defect-like character with significant exciton binding energies (~ 0.1 eV). We discuss the implications of these defect-induced-states for the electron transport and optical properties of GaN.
iii -氮化物具有较大的带隙、较高的载流子漂移速度和较高的击穿电压,是一类宽禁带半导体,在光电子技术中有着广泛的应用。特别是,氮化镓及其合金作为固态照明、射频和电力电子器件的组件材料很有前途。然而,这些材料通常以高缺陷密度生长,这会大大降低其电子和光学性能。因此,准确和详细地了解缺陷对其电子结构的影响将是设计新型高性能材料的核心。本文采用密度泛函理论(DFT)和多体微扰理论(MBPT)来描述缺陷氮化镓的激发态。利用GW/BSE近似中的MBPT,我们开发了一种系统地识别缺陷及其相关阱态能量的方法。对于块体GaN中带+1电荷的氮空位,预测的能带结构表明,这种特殊的缺陷导致在能带边缘附近形成具有陷阱态能量的浅缺陷态。然而,对电子-空穴相关函数的分析表明,低能激发是由类体和类缺陷混合的特征组成的,具有显著的激子结合能(~ 0.1 eV)。我们讨论了这些缺陷诱导态对氮化镓的电子输运和光学性质的影响。