准分子激光辐照法改善GaN外延片性质并增强GaN基LED发光性能

Enhancing Luminescent Properties of GaN-Based LED and Improving Optical and Electrical Properties of GaN Epitaxial Wafers with Excimer Laser Irradiation

采用不同能量密度、脉冲数的248nm准分子激光对表面为p型的GaN外延片进行辐照,再对样品进行退火处理。对激光辐照前后以及退火前后的样品进行光致发光、阴极射线谱、X射线光电子谱、霍尔效应、I-V曲线等表征。实验结果表明:激光辐照和N2气氛下退火相结合可以使GaN外延片的电学和发光性能均较辐照前有不同程度的提高。将改性后的GaN外延片封装成发光二极管(LED)器件,研究了其发光性能与激光辐照能量密度和退火气氛的关系。改性后的GaN基LED器件的发光强度最高可增加约37%,说明GaN外延片电学和发光性能的改善将直接影响其封装成LED器件后的发光性能,这对于提高GaN基LED的性能有重要意义。

The GaN epitaxial wafers with a p-GaN surface are irradiated with an excimer laser at different energy densities and pulse numbers. The laser irradiation induced changes in optical and electrical properties of Ga N epitaxial wafers are examined using photoluminescence, cathode luminescence, X-ray photoelectron spectroscopy,Hall, I-V characterization. Experimental results show that under an appropriate laser irradiating condition and annealing treatment in N2, the luminescent and electrical properties of the samples are improved to different degrees.The irradiated and annealed samples are transformed into light emitting diode（LED） device with semiconductor packing process, and the relationship between the luminescent properties of LED and the laser energy density or annealing atmosphere are investigated. After laser irradiaiton and annealing treatment, the light output power of GaN- based LED increases at least about 37% compared with non- irradiated samples, which shows that the improvement of the electrical properties of GaN epitaxial materials plays important role in enhancing the luminescent properties of the LED device.