硅掺杂铝镓氮薄膜场发射性能研究

利用脉冲激光沉积,分别制备了一系列不同Si掺杂浓度的铝镓氮(AlGaN)薄膜.对此薄膜进行场致电子发射测试表明,Si掺杂浓度为1％的AlGaN薄膜具有最好的场发射特性.相对于非掺杂样品,其场发射电流明显增加,场发射开启电场显著降低.掺杂带来载流子浓度的提升,为场发射提供足够的电子源,使样品的场发射性能提升.但掺杂浓度的进一步提高,薄膜缺陷增加,电子迁移率降低,其薄膜内部电子输运能力降低大于电子浓度的增加对场电子发射的贡献,导致场发射性能开始变差.

Field emission properties of silicon doped AlGaN thin film

Aluminum gallium nitride (AlGaN) thin films are prepared by pulsed laser deposition with different silicon doping concentrations from 0.5% to 2%. The field emission measurement shows that the 1% Si-doped AlGaN film has the best field emission property. Compared with undoped film, the Si-doped film has a large emission current density and a low threshold field. The increase of doping concentration can increase the carrier concentration, which will add a number of supply electrons, thereby improving greatly the FE property of AlGaN film. With the doping concentration further increasing, the defect of film increases and the electron mobility reduces. The reduction of the internal supply electron is greater than the contribution of the increase of electrons concentration, which induces the field emission performance to deteriorate. This study will provide a reliable basis for designing high-performance field emission devices.