Determination of Nitride Semiconductor Parameters Using Light-Induced Transient Gratings

我们提出了在gan基三元和四元材料和器件中产生的电子和空穴的实验和理论研究，包括在紫外范围内具有带隙的化合物。我们将使用光致瞬态光栅（LITG）系统，该系统利用非破坏性技术，包括准稳态和时间分辨光致发光光谱，在不同波长的激光激发下，温度范围为8 K至600 K。我们的研究将包括不同温度下的发光，激发强度和波长的研究，时间分辨发光，受激辐射的研究，以及LITG测量。这将使我们能够确定载流子密度、寿命、扩散系数和表面复合率（映射大面积晶圆）在整个可见范围内到紫外线。将基于LITG的新技术所获得的结果与传统发光光谱的结果进行比较，将为研究宽频隙氮化物在发光和探测器件中的应用提供新的视角。氮基宽带隙半导体的物理特性在许多关键领域与更传统的半导体（如硅或砷化镓）有很大不同。这与一种不同的（更复杂的）对称有关，这种对称允许自发极化。确定氮化物的基本半导体参数，并在适当的情况下将其与材料生长和制造过程联系起来，对于开发新的宽带半导体科学以及支持从固态照明到超高功率雷达，从水净化到生物危害检测等应用的工业至关重要。

We propose experimental and theoretical investigations of light generatedelectrons and holes in GaN-based ternary and quaternary materials anddevices, including compounds with band gap in UV range. We will use Light-Induced Transient Gratings (LITG) system, which exploitsnondestructive techniques including the quasi-steady-state and time-resolvedphotoluminescence spectroscopy in the temperature range from 8 K to 600 Kunder laser excitation at different wavelengths. Our studies will include studies of luminescence at different temperatures,excitation intensities and wavelengths, time-resolved luminescence,investigations of stimulated emission, and LITG measurements. This willallow us to determine carrier densities, lifetimes, diffusion coefficients,and surface recombination rates (mapping large area wafers) throughout thevisible range into UV.Comparison of results obtained by the new technique based on LITG with theresults of the conventional luminescence spectroscopy will provide a newinsight into the problems, which are of the primary importance forexploitation of the wide-band-gap nitrides in light emitting and detectingdevices.Physics of nitride-based wide band gap semiconductors is dramaticallydifferent in many key areas from that of more conventional semiconductors,such as silicon or GaAs. This is linked to a different (and more complex)symmetry that allows for spontaneous polarization. Determining basicsemiconductor parameters for nitrides and relating them to the materialsgrowth and fabrication process, where appropriate, is crucial for developingnew wide band semiconductor science and for supporting industry withapplications ranging from solid state lighting to ultra high power radars,from water purification to biological hazard detection.