Pt/β-Ga_(2)O_(3)深紫外肖特基光电二极管的界面载流子注入和自驱动特性

Comprehensive Investigation of Pt/β-Ga_(2)O_(3) Deep-UV Schottky Photodiode Highlighting Effective Carriers Injection and Self-powered Operation

采用金属有机化学气相沉积技术在c面蓝宝石衬底上生长氧化镓薄膜,再通过光刻、剥离、电子束蒸镀技术在氧化镓薄膜的表面制作非对称叉指电极,其中Pt/Au作为肖特基电极,Ti/Al/Ni/Au作为欧姆电极;为实现良好的欧姆接触,提升界面载流子的注入效率,对沉积Ti/Al/Ni/Au后的样品进行退火处理。相关结果表明,该Pt/β-Ga_(2)O_(3)肖特基光电二极管具有良好的深紫外探测水平。在-5 V偏压下,响应度和外量子效率分别为3.4 A/W和1.66×10~3%。探测器的探测度高达10^(13) Jones,表明其具有优异的弱信号探测能力。同时,响应度和外量子效率整体都随着光强增大而减小,这是由于较高的光生载流子浓度提高了电子-空穴对的复合机率。在自驱动模式下,该Pt/β-Ga_(2)O_(3)肖特基光电二极管展现出较快的响应速度,响应度为2.69 m A/W。此外,探测器在-100 V和+100 V的高压下仍然能够稳定运行,说明该探测器具有较好的耐高压稳定性。

In this paper,Ga_(2)O_(3) thin film was grown on c-plane sapphire substrate by metalorganic chemical vapor deposition(MOCVD),and then asymmetric electrodes were fabricated on the surface of Ga_(2)O_(3) thin film by photoli-thography,lift-off,and electron beam evaporation.Pt/Au was used as the Schottky electrode,and Ti/Al/Ni/Au was used as the Ohmic electrode.In order to achieve good Ohmic contact and improve the injection efficiency of interface carriers,the corresponding annealing treatment is carried out.The relevant results show that the Pt/β-Ga_(2)O_(3) Schott-ky photodiode has a good level of deep ultraviolet detection.At-5 V bias,the responsivity and external quantum effi-ciency was 3.4 A/W and 1.66×103%,respectively.The detectivity was up to 1013 Jones,indicating that it has excel-lent weak signal detection capability.At the same time,the responsivity and external quantum efficiency decrease with the increase of light intensity,which is due to the higher concentration of photogenerated carriers which improves the recombination probability of electron-hole pairs.In self-powered mode,the Pt/β-Ga_(2)O_(3) Schottky photo-diode exhibited a fast responsivity of 2.69 mA/W.In addition,the detector can still operate stably under high volt-age of-100 V and+100 V,indicating that the detector has good stability against high voltage operation.