Yakimova R, Steinhoff G, Petoral R M, Vahlberg C, Khranovskyy V, Yazdi G R, Uvdal K, Lloyd Spetz A
Linköping University, Department of Physics, Chemistry and Biology, SE-58183 Linköping, Sweden.
Biosens Bioelectron. 2007 Jun 15;22(12):2780-5. doi: 10.1016/j.bios.2006.12.032. Epub 2007 Jan 9.
The objectives of this work are to contribute to the knowledge about physical and chemical properties of WBG semiconductors, such as ZnO and GaN towards development of advanced bio- and chemical sensors. For the semiconductors, growth techniques typically yielding single crystal material are applied. Thin epitaxial quality films of ZnO and GaN are fabricated on SiC or sapphire substrates. An emphasis is given to ZnO due to the interesting combination of the semiconductor and oxide properties. Surface bio-functionalization of ZnO is performed by APTES, MPA or MP-TMS molecules. We have compared some of the results to (hydroxylated) GaN surfaces functionalized by MP-TMS. The covalent attachment of the self-assembled biomolecular layers has been proven by XPS analysis. For complementary electrical characterization impedance spectroscopy measurements were performed. The results are intended to serve the realization of bioelectronic transducer devices based on SiC or GaN transistors with a ZnO gate layer. To take advantage of the catalytic properties of ZnO, initial prototypes of chemical sensors for gas sensing are processed on ZnO deposited either on SiC or on sapphire and they are further tested for the response to reducing or oxidizing gas ambient. The sensor devices show sensitivity to oxygen in the surface resistivity mode while a Pt Schottky contact ZnO/SiC device responds to reducing gases. These results are compared to published results on Pt/GaN Schottky diodes.
这项工作的目标是增进对宽带隙（WBG）半导体（如氧化锌和氮化镓）物理和化学性质的了解，以推动先进生物传感器和化学传感器的发展。对于这些半导体，采用了通常能产生单晶材料的生长技术。在碳化硅或蓝宝石衬底上制备了氧化锌和氮化镓的外延高质量薄膜。由于半导体和氧化物性质的有趣结合，重点研究了氧化锌。通过3-氨丙基三乙氧基硅烷（APTES）、巯基丙酸（MPA）或巯丙基三甲氧基硅烷（MP-TMS）分子对氧化锌进行表面生物功能化。我们将一些结果与通过MP-TMS功能化的（羟基化）氮化镓表面进行了比较。X射线光电子能谱（XPS）分析证实了自组装生物分子层的共价连接。为了进行互补的电学表征，进行了阻抗谱测量。这些结果旨在用于实现基于具有氧化锌栅极层的碳化硅或氮化镓晶体管的生物电子换能器器件。为了利用氧化锌的催化特性，在沉积于碳化硅或蓝宝石上的氧化锌上制备了用于气体传感的化学传感器的初始原型，并进一步测试了它们对还原或氧化气体环境的响应。传感器器件在表面电阻率模式下对氧气敏感，而铂肖特基接触的氧化锌/碳化硅器件对还原气体有响应。将这些结果与关于铂/氮化镓肖特基二极管的已发表结果进行了比较。
