利用吸收光谱和光致发光(PL)光谱研究了氢化物气相外延(HVPE)法生长的GaN厚膜材料发光特性。研究发现当激发脉冲光源的重复频率较低时，PL光谱中仅能观察到带边发光峰，当重复频率增加时，PL光谱中不仅出现带边发光峰，还可观察到蓝带发光峰和黄带发光峰；随着光源重复频率的增加，带边发光峰与黄带发光峰、蓝带发光峰的光强之比也随着增大。分析认为蓝带发光起源于材料中碳杂质缺陷而黄带发光可能与位错等结构缺陷有关。

Unintentionally doped GaN thick film grown on (0001) oriented Al2O3 substrate by hydride vapor phase epitaxy (HVPE) is studied in experiments, by absorption spectra and photoluminescence (PL) spectrum. The blue and yellow luminescence at room temperature are observed. The results indicate that when the frequency is low, the PL spectrum is contained by only band-side emission; however, when the frequency becomes high, there are three emission bands (band-side emission, blue emission and yellow emission). Meanwhile, the higher of the frequency, the larger of I1(intensity of band-side emission) /I2 (intensity of blue emission) and I1/I3 (intensity of yellow emission). After calculation and analysis, it can be considered that the blue luminescence is related with the impurity C of the sample, and the yellow luminescence is related with the structure defects like as dislocations.