GaN厚膜中的质子辐照诱生缺陷研究

Study on proton irradiation induced defects in GaN thick film

本文采用正电子湮没谱研究质子辐照诱生缺陷,实验发现:能量为5MeV的质子辐照在GaN厚膜中主要产生的是Ga单空位,没有双空位或者空位团形成;在10K测试的低温光致发光谱中,带边峰出现了"蓝移",辐照后黄光带的发光强度减弱,说明黄光带的起源与Ga空位(VGa)之间不存在必然的联系,各激子发光峰位置没有改变,仅强度随质子注量发生变化;样品(0002)面双晶XRD扫描曲线的半峰宽在辐照后明显增大,说明质子辐照对晶格的周期性产生了影响,薄膜晶体质量下降.

Proton-irradiation-induced defects threaten seriously the stable performance of GaN-based devices in harsh environments, such as outer space. It is therefore urgent to understand the behaviors of proton-irradiation-induced defects for improving the radiation tolerance of GaN-based devices. Positron annihilation spectroscopy （PAS） has been used to study proton-induced defects in GaN grown by HVPE. The result shows that VGa is the main defects and no （VoaVN） or （VGaVN）2 is formed in 5 MeV proton-irradiated GaN. Photoluminescence （PL） spectrum is carded out at 10K. After irradiation, the band edge shows a blue-shift, but the donor- acceptor pair （DAP） emission band and its LO-phonon replicas is kept at the original position. The intensity of yellow luminescence （YL） band is decreased, which means that the origin of YL band has no relation with Vca. The increased FWHM of GaN （0002） peak in proton-irradiated GaN indicates a degradation of crystal quality.