SBIR Phase I: Development of High-Power Green LED

这个小型企业创新研究（SBIR）第一阶段项目将进行可行性研究，以开发在绿色光谱区发光的发光二极管（LED）。需要有效的发射绿色的LED，其用作单独使用的绿色源，并且还用于利用三种或更多种颜色的直接颜色混合的LED灯，红色、绿色和蓝色，以实现白色。绿色LED源通常由氮化铟镓（InGaN）半导体材料制成;然而，随着操作电流增加，这种LED的效率降低。本研究的目的是开发一种绿色LED在高电流值下具有高量子效率，通过减少在工作电流值下观察到的效率下降。这一研究目标将通过在晶片制造过程中形成由沉积在InGaN晶片的量子阱区域上的p型氧化锌（ZnO）半导体层组成的混合LED来实现。p型ZnO层将提供额外的空穴载流子，从而提高量子效率。预期的技术结果将是混合LED器件的效率提高至少20%。 该项目的更广泛的影响/商业潜力将增强对以下机制的技术和科学理解，通过该机制，具有高空穴浓度的p型ZnO半导体材料层在晶片生长期间沉积在由InGaN量子威尔斯组成的有源层区域附近，可以显著增加由这种晶片制造的混合LED器件的量子效率。潜在的社会影响是通过采用更高效率的电气照明来节省美国的能源，从而减少电力需求和明亮的彩色显示器。该项目的潜在商业影响是具有足够高效率的绿色LED的可用性，其与蓝色和红色LED组合使用，以通过直接颜色混合来实现商业上可行的白色LED灯，而不使用磷光体来从蓝色实现绿色光。直接颜色混合方法将消除与使用下转换磷光体相关联的低效率。这些直接混色的LED灯将具有成本效益，并具有消费者所需的光谱质量，这将有助于加快市场进入。受影响的市场部门包括半导体芯片制造、住宅和商业用白色灯以及彩色显示器。

This Small Business Innovative Research (SBIR) Phase I project will conduct feasibility studies for development of light emitting diodes (LEDs) that emit in the green spectral region. A need exists for efficient green emitting LEDs for use as a green source used singly and also for use in LED lamps that utilize direct color-mixing of three or more colors, e.g., red, green and blue, to achieve white. Green LED sources are typically made from indium gallium nitride (InGaN) semiconductor material; however, such LEDs suffer from a decrease in efficiency as operating current is increased. The research objective is to develop a green LED with high quantum efficiency at high current values by reducing the observed efficiency droop at operating current values. This research objective will be achieved by forming a hybrid LED comprised of a p-type zinc oxide (ZnO) semiconductor layer deposited on the quantum well region of an InGaN wafer during the wafer fabrication process. The p-type ZnO layer will provide additional hole carriers and thereby increase quantum efficiency. The anticipated technical results will be an increased efficiency of at least 20% for the hybrid LED device. The broader impact/commercial potential of this project will enhance technical and scientific understanding of the mechanisms by which a layer of p-type ZnO semiconductor material with high hole concentration and deposited during wafer growth in close proximity to the active layer region comprised of InGaN quantum wells can increase significantly the quantum efficiency of the hybrid LED device fabricated from such wafers. A potential societal impact is energy savings for the U.S. by employing higher efficiency electrical lighting and thereby decreasing electrical power demand and bright color displays. The potential commercial impact of the project is availability of a green LED with sufficiently high efficiency to be utilized in combination with blue and red LEDs to achieve a commercially viable white LED lamp by direct color-mixing, without use of phosphors to achieve green light from blue. A direct color mixing approach will eliminate inefficiencies associated with use of down-converting phosphors. These direct color-mixed LED lamps will be cost effective and possess spectral qualities desirable to consumers that will help speed market entry. The market sector impacted includes semiconductor chip manufacturing, white light lamps for residential and commercial use, and color displays.