低暗计数率InGaAsP/InP单光子雪崩二极管

通过对InGaAsP/InP单光子雪崩二极管（SPAD）的探测效率、暗计数率等基本特性与该器件的禁带宽度、电场分布、雪崩长度、工作温度等参数之间关系的分析，采用比通常的InxGaAs （x=0.53）材料具有更宽带隙的InxGa1-xAsyP1-y（x=0.78，y=0.47）材料作为光吸收层，并且精确控制InP倍增层的雪崩长度，有效地降低了SPAD的暗计数率。其中InGaAsP材料与InP材料晶格匹配良好，可在InP衬底上外延生长高质量的InGaAsP/InP异质结，InGaAsP材料的带隙为Eg=1.03 eV，截止波长为1.2 m，可满足1.06 m单光子探测需要。同时，通过设计并研制出1.06 m InGaAsP/InP SPAD，对其特性参数进行测试，结果表明，当工作温度为270 K时，探测效率20%下的暗计数率约20 kHz。因此基于时间相关单光子计数技术的该器件可在主动淬灭模式下用于随机到达的光子探测。

Low dark count rate InGaAsP/InP SPAD

The relationship among the characteristics of InGaAsP/InP SPAD, such as photon detection efficiency(PDE) and dark count rate(DCR), and the parameters of the SPAD, like InGaAsP band gap,electric field distribution, avalanche length and operating temperature, was analyzed. The DCR of the SPAD was effectively decreased by using the InxGa1-xAsyP1-y(x=0.78, y=0.47) as photon absorption layer instead of the InxGaAs(x=0.53) and controlling avalanche length of InP multiplication region precisely. According to good lattice matching of InGaAsP and InP, high quality InGaAsP/InP heterojunction was epitaxially grown on InP substrate to detect single photon of 1.06 m, with 1.03 eV band gap and 1.2 m cutoff wavelength. InGaAsP/InP SPAD was designed and manufactured for 1.06 m detection. And measurement results show that DCR is about 20 kHz under 20% PDE on 270 K. The device can detect random arrival photons based on time correlated single photon counting technique under active quenching mode.