B-N Codoped p Type ZnO Thin Films for Optoelectronic Applications

The success of codoping by donor-acceptor impurities in accomplishing p type ZnO thin films deposited by spray pyrolysis technique is reported here. Monodoping ZnO with N altered the conductivity type but the resistivity is too high making it practically impossible to be useful in optoelectronic applications. B-N codoping increased the carrier concentration and obtained comparatively low resistivity because codoping enhanced the acceptor incorporation by forming acceptor-donor-acceptor complex in the band gap. XRD analysis revealed the dependence of dopant incorporation on the texture and microstructure of the films. XPS analysis confirmed the enhancement of N incorporation with codoping. Energy gap value increased for codoped films due to the Burstein-Moss effect, arising from the increase in carrier concentration. Hence the present work envisages the preparation of transparent p type ZnO thin films suitable for tandem thin film solar cells and also for other optoelectronic applications.

本文报道了通过供体-受体杂质共掺杂工艺，成功制备喷雾热解法沉积的p型氧化锌（ZnO）薄膜的研究结果。仅以氮（N）单掺杂氧化锌，虽可改变其导电类型，但电阻率过高，实际无法满足光电子应用的需求。硼（B）-氮（N）共掺杂则提升了载流子浓度，获得了相对较低的电阻率——这是由于共掺杂通过在禁带中形成受主-施主-受主复合物，增强了受主杂质的掺入效率。X射线衍射（XRD）分析显示，掺杂剂的掺入量与薄膜的织构及微观结构密切相关。X射线光电子能谱（XPS）分析证实，共掺杂可有效提升氮元素的掺入量。由于载流子浓度升高引发的伯斯坦-莫斯（Burstein-Moss）效应，共掺杂薄膜的禁带宽度有所增大。因此，本研究成功制备出适用于叠层薄膜太阳能电池及其他光电子应用的透明p型氧化锌薄膜。