关于Ga_(2)O_(3)/Al_(0.1)Ga_(0.9)N同型异质结的双波段、双模式紫外探测性能分析

Dual-band and dual-mode ultraviolet photodetection characterizations of Ga_(2)O_(3)/Al_(0.1)Ga_(0.9)N homo-type heterojunction

鉴于紫外探测器在诸多领域的重要应用,探寻自供电型探测器以及挖掘其内在运行机理显得尤为关键.本文制备的Ga_(2)O_(3)/Al_(0.1)Ga_(0.9)N异质结紫外探测器能够实现对254 nm波长(UVC波段)和365 nm(UVA波段)波长紫外光的敏感探测,并在不同方向的偏压驱动下能够实现耗尽模式和光电导模式的光探测.这里介绍的基于Ga_(2)O_(3)/Al_(0.1)Ga_(0.9)N异质结的双波段、双模式紫外光电探测器具有理想的暗电流和光响应特性;在5和–5 V偏压下,在254 nm光照射下的光响应度分别为2.09和66.32 mA/W,在365 nm光照射下的光响应度分别为0.22和34.75 mA/W.并且仅在内建电场的作用下能够自供电运行,对254和365 nm波长紫外光的光响应度为0.13和0.01 mA/W.进一步,除对材料与器件性能的表征与解析,本文还从异质结探测器的运行机理上分析了其双波段与双模式探测特性.

The deep-ultraviolet(DUV)photodetectors(PDs)have important applications in lots of fields.Thus,developing self-powered DUV PDs and excavating the inherent mechanism seem seriously crucial to achieving further actual applications.The construction of heterojunction can lead to many desired characteristics in optoelectronic devices.In the field of DUV photodetection,Ga_(2)O_(3)has been a popular subject for constructing DUV PDs.So,it is necessary to develop self-powered Ga_(2)O_(3)-based DUV PDs through fabricating its heterogeneous structure.Therefore,in this work,the Ga_(2)O_(3)/Al_(0.1)Ga_(0.9)N heterojunction DUV PD is fabricated and discussed,which can achieve 254 and 365 nm DUV light photodetection.At positive voltages and negative voltages,the heterojunction PD can operate in a photoconductive mode or a depletion mode,respectively.In view of the PD performance,it displays decent dark current and DUV photoresponses.At voltage of 5 and–5 V,under 254 nm DUV light illumination,the photoresponsivity(R)is 2.09 and 66.32 mA/W,respectively,while under 365 nm DUV light illumination,R is 0.22 and 34.75 mA/W,respectively.In addition,under the built-in electric field(Ebuilt-in),R is 0.13 and 0.01 mA/W for 254 nm and 365 nm DUV light illumination,respectively.In all,the fabricated heterojunction PD displays promising prospects in the coming next-generation semiconductor photodetection technology.The results in this work indicate the potential of Ga_(2)O_(3)/Al_(0.1)Ga_(0.9)N heterojunction with high performance DUV photodetection.Furthermore,except for the characterizations of the materials and photodetector,in the end of this paper,the operating mechanism of the dual-band dual-mode heterojunction PD is analyzed through its heterogeneous energy-band diagram.It is concluded that the illustrated dual-band dual-mode Ga_(2)O_(3)/Al_(0.1)Ga_(0.9)N heterojunction can be sensitive to UVA waveband and UVC waveband in the electromagnetic spectrum,extending its photodetection region.And,the dual-mode(photoconductive mode and depletion mode)photodetection indicates two kinds of carrier transports in one PD,which can be attributed to the successful construction of the N-N tomo-type Ga_(2)O_(3)/Al_(0.1)Ga_(0.9)N heterojunction.