立方相GaN的持续光电导

研究了金属有机物化学气相外延(MOVPE)方法生长的非故意掺杂的立方相GaN的持续光电导效应.在六方相GaN中普遍认为持续光电导效应与黄光发射有关,而实验则显示在立方GaN中,持续光电导效应与其中的六方相GaN夹杂有关系,而与黄光发射没有关系.文中提出,立方相GaN与其中的六方相GaN夹杂之间的势垒引起的空间载流子分离是导致持续光电导现象的物理原因.通过建立势垒限制复合模型,解释了立方相GaN的持续光电导现象的物理过程,并对光电导衰减过程的动力学作了分析.对实验数据拟合的结果证明以上的模型和推导是与实验相符的.     

Effects of growth temperature on high-quality In_(0.2)Ga_(0.8)N layers by plasma-assisted molecular beam epitaxy

正High-quality In_(0.2)Ga_(0.8)N epilayers were grown on a GaN template at temperatures of 520 and 580℃via plasma-assisted molecular beam epitaxy.The X-ray rocking curve full widths at half maximum(FWHM) of(10.2) reflections is 936 arcsec for the 50-nm-thick InGaN layers at the lower temperature.When the growth temperature increases to 580℃,the FWHM of(00.2) reflections for these samples is very narrow and keeps similar,while significant improvement of(10.2) reflections with an FWHM value of 612 arcsec has been observed.This improved quality in InGaN layers grown at 580℃is also reflected by the much larger size of the crystalline column from the AFM results,stronger emission intensity as well as a decreased FWHM of room temperature PL from 136 to 93.9 meV.     

Lanxide技术合成含烧结助剂的复合AIN粉体

高纯度的氮气中，以Al-Mg-Y合金为母合金，利用Lanxide技术合成了含烧结助剂Y2O3的复合AlN粉体。通过扫描电镜、X射线衍射、粒径分析及化学成分分析等检测手段对氮化产物进行表征。实验结果表明，合金氮化反应完全，氮化产物疏松易于粉化，粉化后获得的复合AlN粉体具有纯度高，氧杂质含量低，粒度细小等优点。     

Wafer bonding technique used for the integration of cubic GaN/GaAs (001) with Si substrate

We successfully used the metal mediated-wafer bonding technique in transferring the as-grown cubic GaN LED structure of Si substrate. The absorbing GaAs substrate was removed by using the chemical solutions of NH4OH : H2O2=1 : 10. SEM and PL resuls show that wafer bonding technique could transfer the cubic GaN epilayers uniformly to Si without affecting the physical and optical properties of epilayers. XRD result shows that there appeared new peaks related to AgGa2 and Ni4N diffraction, indicating that the metals used as adhesive and protective layers interacted with the p-GaN layer during the long annealing process. It is just the reaction that ensures the reliability of the integration of GaN with metal and minor contact resistance on the interface.     

柔性衬底上使用等离子增强原子层沉积制备的氮化镓薄膜物性分析

采用等离子增强原子层沉积技术（PE-ALD）在350℃温度下,在KAPTON柔性衬底上直接生长出多晶GaN薄膜。利用低角度掠入射X射线衍射仪、AFM、SEM、TEM、XPS对薄膜的晶体结构、表面形貌及薄膜成分进行了表征和分析。结果表明,薄膜呈多晶态,且具有良好的均匀性;薄膜中的N元素全部以N-Ga键形式存在;大部分Ga元素以Ga-N键形式构成GaN;少量的Ga元素分别以Ga-Ga键和Ga-O键形式构成金属镓以及Ga2O3。研究发现,虽然KAPTON具有较好的耐高温性,但GaN会反向扩散进入KAPTON衬底,形成具有一定厚度的GaN扩散层。     

In—Situ Synthesis of AlNPowders and Composite AlN Powders with Yttrium Addition

Ａｌｕｍｉｎｕｍｎｉｔｒｉｄｅ (ＡｌＮ) ,ｄｕｅｔｏｇｏｏｄｐｈｙｓｉｃａｌａｎｄｍｅｃｈａｎｉｃａｌｐｒｏｐｅｒｔｉｅｓ ,ｉｓｓｕｉｔａｂｌｅｆｏｒｍｕｌｔｉｌａｙｅｒｌａｙｏｕｔａｎｄｉｓｃｏｎｓｉｄｅｒｅｄａｓａｐｒｏｍｉｓｉｎｇｍａｔｅｒｉａｌｆｏｒｓｕｂｓｔｒａｔｅ ,ｅｌｅｃｔｒｏｎｉｃｐａｃｋｉｎｇａｎｄｌａｒｇｅ ｓｃａｌｅｉｎｔｅｇｒａｔｅｄｃｉｒｃｕｉｔ[1～ 4] .Ｉｎａｄｄｉｔｉｏｎ ,ｉｔｉｓｗｉｄｅｌｙｕｓｅｄｉｎｔｈｅｏｐｔｏｅｌｅｃ ｔｒｏｎｉｃｆｉｅｌｄ ,ｓｕｃｈａｓＭＯＤ…     

InGaN/GaN多量子阱电池的垒层结构优化及其光学特性调控

InGaN基量子阱作为太阳电池器件的有源区时,垒层厚度设计以及实际生长对其光学特性的影响极为重要.采用金属有机化学气相沉积(MOVCD)技术,在蓝宝石衬底上外延生长了垒层厚度较厚的InGaN/GaN多量子阱,使用高分辨X射线衍射和变温光致发光谱研究了垒层厚度对InGaN多量子阱太阳电池结构的界面质量、量子限制效应及其光学特性的影响.较厚垒层的InGaN/GaN多量子阱的周期重复性和界面品质较好,这可能与垒层较薄时对量子阱的生长影响有关.同时,厚垒层InGaN/GaN多量子阱的光致发光光谱峰位随温度升高呈现更为明显的“S”形(红移-蓝移-红移)变化,表现出更强的局域化程度和更高的内量子效率.