Fig. 1. History of infrared photodetectors.红外探测器发展历史

Fig. 2. Raytheon company investigates the use of photon trapping structures with varying fill factor in HgCdTe detectors for use in mid-wavelength infrared (MWIR) detectors^[22]. 美国Raytheon公司制备的不同陷光结构的中波HgCdTe红外探测^[22]

Fig. 3. Photo-trapping (PT) structure^[23]: (a) Schematic representing a single pixel of an array with 8 μm pixels; (b) three dimensional view of 3 × 3 pixel array. HgCdTe陷光结构^[23] 　(a)像元间距为8 μm的HgCdTe红外探测器阵列的单个像元示意图; (b) 3 × 3阵列像元阵列三维示意图

Fig. 4. Calculated (a) reflectance spectra and (b) quantum efficiency for a single 6 μm pixel of the PT and non-PT arrays^[23]. 单个像元间距为6 μm的陷光结构与非陷光结构阵列数值模拟的(a)反射谱和(b)量子效率^[23]

Fig. 5. (a) Schematic of the Si photodiode; (b) the n-i-p photodiode structure on an silicon-on-insulator (SOI) wafer, the integrated tapered holes that span the n, i and p layers^[24]. (a) Si光电二极管的示意图; (b) Si晶元衬底上的n-i-p光电二极管, 锥形小孔贯穿n, i, p层^[24]

Fig. 6. FDTD numerical simulations show the formation of lateral electric field modes around holes when illuminated by a normal incident beam of light^[24]: (a) Cylindrical holes; (b) funnel-shaped holes. Top, X-Y plane; bottom, Y-Z plane. Time increased from left to right: T = 1.4, 6.2, 11, 16, 21 fs. FDTD数值模拟在垂直光照射时小孔周围横向电场的模式(顶部是XY截面, 底部为YZ截面; 时间从左到右增加, T = 1.4, 6.2, 11, 16, 21 fs)^[24] 　(a)圆柱形小孔; (b)漏斗形小孔

Fig. 7. Representation of surface plasmon polaritons: Under the excition of injection light, the density of electrons in the surface of metal experience a little change, which correspond to the collective excition modes of surface electrons.表面等离激元波示意图(金属表面的电子对入射光的响应产生了表面几十纳米内的电子密度的轻微扰动, 构成了金属中表面电子的集体激发模式)

Fig. 8. (a) Fabrication steps of the metal grating; (b) SEM photograph of GaAs; (c) streamline diagram of Poynting vector. At the resonance wavelength of 10.05 μm, the light field is almost completely confined into the slit^[31]. (a)金属光栅制备过程; (b) GaAs的扫描电子显微镜(scanning electron microscope, SEM)照片; (c)坡印亭矢量的流线图, 可见在共振波长10.05 μm处, 光场被几乎全被限制到了狭缝中^[31]

Fig. 9. (a) Schematic diagram of the SPP structure with the metal hole array on the quantum dot infrared detector^[32]; (b) SEM photograph of the metal hole array SPP structure^[32]; (c) SEM photograph of the bull's eye detector^[33]; (d) the bull's eye structure with slit^[34]; copyright 2011 American Chemical Society (e) schematic diagram of graphene-surface plasmon photodetector^[35]; (f) polarization dependent multi-wavelength SPP structure^[36]. (a)量子点红外探测器上覆盖金属孔洞阵列SPP结构的器件示意图^[32]; (b)金属孔洞阵列SPP结构的SEM照片^[32]; (c)牛眼探测器的SEM照片^[33]; (d)劈裂牛眼结构^[34]; (e)石墨烯表面等离激元器件结构示意图^[35]; (f)偏振多波长SPP结构^[36]

Fig. 10. (a) Absorption spectra of TiS₂ nanosheets; (b) quantum well infrared detectors enhanced by LSP and SPP together; (c),(d) electric field distribution of nanosheets of LSP resonance and non-resonant mode^[41]; (e) ultra-wide spectrum graphene detector auxiliary by silicon quantum dots^[42]; (f)−(h) Au arrays enhanced MoS₂ phototransistors^[40]. (a) TiS₂纳米片的吸收谱; (b) LSP与SPP共同增强量子阱红外探测器; (c), (d)纳米片的LSP共振与非共振模式下的电场分布图^[41]; (e)硅量子点辅助的超宽谱石墨烯探测器^[42]; (f)—(h)金阵列增强型MoS₂光电二极管^[40]

Fig. 11. The band diagram of plasmon hot electrons. Schottky barrier is ϕ_B. The illuminating light photoexcited electrons in metal, generating electron-hole pairs. Taking conservation of momentum in to consideration, this process may be aided by phonons or impurities^[43]. 等离激元热电子能带图(肖特基势垒为ϕ_B; 电子-空穴对受激光激发; 满足动量守恒要求对应的过程为声子辅助或杂质辅助的)^[43]

Fig. 12. (a) Schematic diagram of LSP-based photodetector; (b) SEM photo of photodetector based on LSP^[43]; (c) schematic diagram of photodetector based on SPP; (d) SEM photograph of photodetector based on SPP thermoelectron; (e) photocurrent mapping of SPP plasmon thermal electronic devices^[44]. (a)基于LSP的光电探测器结构示意图; (b)基于LSP的光电探测器SEM照片^[43]; (c)基于SPP的光电探测器结构示意图; (d)基于SPP热电子的光电探测器SEM照片; (e) SPP等离激元热电子器件的光电流Mapping图^[44]

Fig. 13. Band diagram of quantum cascade detectors.量子级联探测器能带结构示意图

Fig. 14. Diagram of plasmonic micro-cavity coupled QCDs^[56,58]. 表面等离激元微腔结构耦合量子级联探测器结构示意图^[56,58]

Fig. 15. Designs of broadband spectrum QCDs: (a) Double quantum wells absorption; (b) mini-band absorption; (c) low barrier design.宽光谱量子级联探测器设计　(a)双阱吸收; (b)微带吸收; (c)低势垒

Fig. 16. Quantum well coupled In_0.53Ga_0.47As/In_0.52Al_0.48As QCDs^[60]: (a) Band diagram; (b) responsivity; (c) detectivity. 量子阱耦合型In_0.53Ga_0.47As/In_0.52Al_0.48As量子级联探测器^[60] 　(a)能带结构; (b)响应率; (c)探测率

Fig. 17. Band diagram of interband cascade detectors.带间级联探测器能带结构示意图

Fig. 18. (a) Optimization design of relaxation region in ICDs; (b) temperature dependent of the detectivity ^[63]. (a)带间级联探测器弛豫区的优化设计; (b)探测率随温度的变化^[63]

Fig. 19. Responsivity varies with temperature for one stage structure (a) and two stage structure (b) interband cascade detectors ^[64]响应率随温度的变化　(a)单周期结构; (b)双周器结构^[64]

Fig. 20. Comparison of peak detectivity among typical photodetector at room temperature.常温工作时典型探测器峰值探测率对比

Fig. 21. (a) Energy band diagram for interpretation of optical gain in graphene/quantum dots heterostructure^[74]; (b) schematic diagram of CMOS integrated graphene/quantum dots focal array plane^[75]; (c) schematic diagram of mid-infrared pure black phosphorous photodetector^[73]; (d) high gain and high responsivity InAs nanowire^[76]; (e) high performance mid-wavelength InAs nanowire^[77]. (a)石墨烯/量子点复合结构增益原理图^[74]; (b) CMOS集成的石墨烯/量子点焦平面结构示意图^[75]; (c)室温中红外高增益黑磷探测器结构示意图^[73]; (d)室温高增益高响应InAs纳米线^[76]; (e)室温高性能中红外InAs纳米线^[77]

Fig. 22. (a) Schematic diagram of photovoltage field-effect transistors^[78]; (b) gain-bandwidth product for different types of photodetectors^[65]; (c) schematic diagram of mid-infrared graphene detector through interfacial gating of InSb; (d) the photoresponse of device in (c) at various temperatures^[78,80]. (a)光伏场效应晶体管示意图^[78]; (b)不同器件的增益带宽积^[65]; (c) InSb作光敏介质调控石墨烯器件结构示意图; (d)器件不同工作温度下的响应^[78,80]

Fig. 23. (a) The ferroelectric hysteresis loop 300 nm P(VDF-TrFE) film capacitor; (b) the I_ds-V_dscharacteristics (at ZERO gate voltage) with three states of ferroelectric layer, and the three states are fresh state (ferroelectric layer without polarization), polarization up (polarized by a pulse V_g of –40 V), and polarization down (polarized by a pulse V_g of –40 V) states, respectively; (c), (d) the cross-section structures of the device and equilibrium energy band diagrams of three different ferroelectric polarization states ^[82]. (a) 300 nm P(VDF-TrFE)薄膜的电滞回线; (b) P(VDF-TrFE)处于三种极化状态下, P(VDF-TrFE)-MoS₂晶体管的I_ds-V_ds曲线, fresh指未极化状态, P up, P down分别代表极化向上和极化向下状态; (c), (d) P(VDF-TrFE)极化向上和极化向下时器件示意图以及能带图^[82]

Fig. 24. (a) The schematic diagram of the graphene-PZT field effect transistor; (b) schematic of a graphene pyroelectric bolometer; (c) working mechanism diagram for the device in panel (b) ^[87]. (a)石墨烯-PZT场效应晶体管结构示意图; (b)石墨烯- LiNbO₃热释电探测器器件结构图; (c)器件的工作原理图^[87]

Fig. 25. (a) Structure diagram of graphene/Ta₂O₅/graphene tunneling diode; (b) infrared responsivity curve of variable incident power with 3.2 μm wavelength; (c) h-BN/b-P/h-BN vertical heterojunction photodetectors; (d) 7.7 μm infrared responsivity of h-BN/b-P/h-BN vertical heterojunction photodetectors^[93,94]. (a) Graphene/Ta₂O₅/graphene隧道结红外探测器结构示意图; (b)多种功率下红外响应曲线, 入射光波长3.2 μm; (c) h-BN/b-P/h-BN垂直异质结的红外探测器; (d) h-BN/b-P/h-BN垂直异质结器件7.7 μm红外光电响应^[93,94]

Fig. 26. (a) Structure diagram of p-g-n heterojunction photodetectors; (b) responsivity of p-g-n heterojunction photodetectors; (c) absorption spectrum of b-As_0.83P_0.17; (d) mid-infrared response of b-AsP/MoS₂ heterojunction photodetectors^[98]. (a) p-g-n异质结光电探测器的结构示意图; (b) p-g-n异质结光电探测器的光电响应; (c)黑砷磷b-As_0.83P_0.17样品的光学吸收谱, 插图为黑砷磷合金b-AsP/MoS₂异质结器件结构示意图; (d) b-AsP/MoS₂异质结光电探测器在中波红外的光电响应^[98]

Fig. 27. BP/MoS2 infrared photodetector^[99]: (a) Photocurrent with 1000 K blackbody source and the dark current; (b) detectivity comparison of typical infrared photodetectors; (c) response time BP与MoS₂异质结红外探测器^[99] (a) 1000 K黑体源辐射下光电流与暗电流; (b)探测率的对比; (c)响应时间

Fig. 28. The tunneling effect (a) and avalanche effect (b) in p-n junction under large reverse bias.传统光伏型红外探测器　(a)和雪崩光电探测器(b)工作时的能带结构图

Fig. 29. MIM structure diagram used for InGaAs/InP avalanche photodiode^[108−110]: (a) Polarization selective structure; (b) non-polarization selective structure; (c) and (d) are the SEM image. InGaAs/InP APD的MIM结构示意图^[108—110] 　(a)偏振选择型结构示意图; (b)无偏振选择型结构示意图; (c), (d)分别为SEM图

Fig. 30. (a) I-V characteristics of BP/InSe APD; (b) noise and gain of BP/InSe APD; (c) traditional ionizing collision process; (d) ballistic avalanche mechanism of BP/InSe APD^[111]. (a) BP/InSe雪崩光电二极管的电流特性; (b)器件的噪声及增益水平; (c)传统的雪崩光电探测器载流子碰撞过程; (d)弹道雪崩效应示意图

Fig. 31. The diagram of ionization process: (a) Hole injection; (b) electron injection.离化过程能带结构示意图　(a)空穴注入型; (b)电子注入型

Fig. 32. The photograph of 128 × 128 HgCdTe APD FPA fabricated in DRS and the average gain^[115]. DRS制备的128 × 128 HgCdTe APD焦平面器件照片和器件平均增益^[115]

Fig. 33. The 3D real time imaging print screen of HgCdTe APD fabricated in Sofradir^[118]. Sofradir公司利用HgCdTe APD 3D实时成像截图^[118]

Fig. 34. The I-V characteristic of planar (a) and mesa (b) HgCdTe APD with variable fabrication process^[121]. 平面结(a)和台面结(b)碲镉汞雪崩光电探测器在不同工艺下的暗电流特性曲线^[121]

Fig. 35. Structure and band diagram of hot carriers infrared photodetectors^[122]. 热载流子红外探测器器件结构和能带示意图^[122]

Fig. 36. Photo response of hot carriers infrared photodetectors^[122]. 热载流子红外探测器的光谱响应^[122]

Fig. 37. Spectral weight diagram of hot carriers infrared photodetectors^[122]. 热载流子红外探测器光谱权重图^[122]

Fig. 38. Spectral weight diagram with variable pump light^[122]. 不同波长泵浦光下器件光谱权重图^[122]

Fig. 39. Structure and band diagram of nBn devices.nBn型器件和能带结构示意图

Fig. 40. Schematic Arrhenius plot of the dark current in a standard diode and XBn device^[127]. 普通PN结二极管器件与XBn器件的暗电流与温度相关性^[127]

Fig. 41. Schematic diagram of (a) design of InSb nBn structure and (b) energy band of InSb nBn structure^[128,129]. InSb nBn探测器(a)器件结构示意图和(b)能带结构示意图^[128,129]

Fig. 42. For InSb nBn infrared photodetectors, the dark current characteristics at (a) 77 K and (b) 104−170 K, (c) the spectral response at 77 K, and (d) the dark current characteristics at different temperatures and structures^[128,129]. nBn结构InSb探测器　(a) 77 K下暗电流特性; (b) 104—170 K暗电流特性; (c) 77 K下光谱响应; (d)不同温度和结构下的暗电流特性^[128,129]

Fig. 43. SWIR InAs/GaSb/AlSb/GaSb nBn detector based on Type-II superlattice: (a) Structure diafram; (b) quantum efficiency; (c) dark current characteristics; (d) detectivity at different temperature^[131]. 短波红外InAs/GaSb/AlSb/GaSb Ⅱ类超晶格nBn探测器　(a)结构示意图; (b)量子效率; (c)暗电流特性; (d)探测率^[131]

Fig. 44. (a) Photograph of long-wavelength infrared (LWIR) InAs/GaSb pBp device based on Type-II superlattice fabricated by Israel SCD company; (b) image at 77 K^[141—143]. 以色列SCD公司制备Pelican-D系列长波探测器　(a)探测器组件; (b) 77 K下成像结果^[141—143]

Fig. 45. The dark current of (a) MWIR and (b) LWIR HgCdTe nBvn, nBn and DLPH devices; (c) and (d) show the detectivity of MWIR and LWIR devices, respectively^[144]. 碲镉汞nBvn, nBn及DLPH器件的(a)中波暗电流、(b)长波暗电流、(c)中波探测率和(d)长波探测率^[144]

Fig. 46. 128 × 128 long-wavelength/mid-wavelength two-color HgCdTe infrared focal plane: (a) Dark current characteristic; (b) spectral response; (c) two-color imaging.128 × 128长波/中波双色碲镉汞红外焦平面探测器　(a)暗电流特性; (b)中波/长波光谱响应曲线; (c)中波长波成像效果

Fig. 47. (a) Structure of HgTe quantum dot dual-band infrared photodetector; (b) temperature dependent short-wavelength and mid-wavelength detectivity; (c) two-color imaging of cold and hot water^[157]. (a) HgTe量子点双色红外探测器结构; (b)双色探测率随温度的变化; (c)冷水与热水的双色成像^[157]