以氮化鋁-氧化鋅/氧化鋅量子井結構製作發光二極體之研究

Investigation on AlN-ZnO/ZnO Quantum Well Structure and Fabrication on Light-Emitting Diode

蔡博升(Bor-Sheng Tsai)

指導教授 ： 劉代山

國立虎尾科技大學/電機資訊學院/光電與材料科技研究所/碩士(2015年)

https://doi.org/10.6827/NFU.2015.00004

摘要

本研究利用射頻磁控共濺鍍系統，以氮化鋁-氧化鋅靶材製作出未摻雜氧化鋅薄膜與氮化鋁-氧化鋅共濺鍍薄膜，並製作出氧化鋅異質結構、氮化鋁-氧化鋅雙異質結構及氮化鋁-氧化鋅量子井結構，針對不同主動層厚度之雙異質結構及量子井結構，以光激發螢光量測與霍爾量測探討其結構之光電特性，霍爾電特性量測顯示薄膜載子濃度有逐漸下降的現象，而光激發螢光量測顯示由於鋁原子擴散影響，雙異質結構及量子井結構皆能抑制未摻雜氧化鋅的本質缺陷-氧缺位，從電激發螢光量測可發現降低主動層厚度可使元件內部載子侷限效應及複合效率提升，主動層厚度為20 nm時，發光波段為420 nm及610 nm，元件發光偏向白光(CIE1931 X=0.3330 Y=0.3138)，當主動層厚度下降至5 nm時，發光波段變為408 nm，元件發光轉為藍紫光(CIE1931 X=0.2615 Y=0.2370)，說明降低主動層厚度確實可提升侷限效應及複合效率，而為了更進一步提升元件發光效能，因而製作多重量子井結構元件，從電激發螢光量測可觀察到，隨著井區對數增加，載子於ZnO層內的侷限效應及複合效率逐漸提升，使得元件發光效能提升，元件發光強度增強，發光峰值產生藍移的現象，當井區對數增加至10對時，元件發光峰值大幅藍移至385 nm，十分接近氧化鋅的本質發光，使得元件發光轉偏為紫光(CIE1931 X=0.2703 Y=0.1893)。此現象證實增加井區對數確實可提升載子的侷限效應及複合效率。由於元件於高電流操作下會有熱效應產生，為了減少熱效應對於元件的影響並提升元件發光效能，因此將載子侷限層從50 nm降低至20 nm及10 nm，經由計算發現串聯電阻從8.33 kΩ降低至6.6 kΩ，由於串聯電阻降低，使得元件內部熱效應減少，元件發光效能提升，元件發光強度提升了約1.29倍。

關鍵字

射頻磁控共濺鍍 ； 氮化鋁 ； 氧化鋅 ； 雙異質結構 ； 量子井結構 ； 多重量子井結構 ； 發光二極體

並列摘要

The study by RF magnetron co-sputtering system, aluminum nitride - zinc oxide target to produce a non-doped zinc oxide and aluminum nitride film - co-sputtered film of zinc oxide and zinc oxide to produce a heterostructure, aluminum nitride - zinc oxide and aluminum nitride double heterostructure - ZnO quantum well structure, for the double heterostructure and quantum well structures of different thickness of the active layer to Photo limuniscence measurement and Hall measurements investigate the structure of the optical and electrical properties, Hall measurements show the electrical characteristics of the film carrier concentration has decreased phenomenon, and Photo limuniscence measurements show since the aluminum atom diffusion effect, a double heterostructure and quantum well structures can suppress the ZnO defect - oxygen vacancy, from Electrical limuniscence measurement can be found that reduce the thickness of the active layer inside the device enables carrier confinement effect and composite efficiency, active layer thickness of 20 nm, the light-emitting wavelength of 420 nm and 610 nm, the light-emitting is tend to white emission(CIE1931 X = 0.3330 Y = 0.3138), when the active layer thickness decreased to 5 nm, emission wavelength becomes 408 nm, the light emitting is tend to blue-violet light emission(CIE1931 X = 0.2615 Y = 0.2370), the result show that reduce the thickness of the active layer can improve the carrier confinement effect and recombination efficiency, and in order to further enhance the element luminous efficacy, thus making a multiple quantum well structure elements from Electrical limuniscence measurement can be observed, as well area of increasing the number of carriers in the ZnO layer confinement effect and gradually increase recombination efficiency, so that the element luminous efficacy improved, the light intensity increased, blue shift of the emission peak generation phenomenon, when the well area to increase the number to 10 period, component emission peak moved sharply Blue 385 nm, very close to the oxidation the nature of the light-emitting ZnO, the light emitting is tend to violet light emission(CIE1931 X = 0.2703 Y = 0.1893). The result prove that increase the number of well region can enhance the effects and limitations of carrier recombination efficiency. Since the elements have thermal effects at high current operation, in order to reduce the thermal effects for components to influence and enhance the element luminous efficacy, so the carrier confining layer from 50 nm decrease to 20 nm and 10 nm, after calculated that the series resistance from 8.33 kΩ decrease to 6.6 kΩ, due to the series resistance is reduced, the thermal effects can be droop, the light emission performance can be improvement, the light emission intensity increased roughly 1.29 times.

並列關鍵字

RF magnetron sputtering ； AlN ； ZnO ； double-heterojunction ； quantum well ； multiple quantum well ； light emitting diode

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