基于蝶形天线耦合 AlGaN/GaN HEMTs 阵列的 0.2-4.0THz 宽带太赫兹探测器。

Opt Express. 2023 Mar 13;31(6):10720-10731. doi: 10.1364/OE.483605.

To satisfy the demand for broadband and high-sensitivity terahertz detectors, we designed and verified a broadband terahertz detector built with antenna-coupled AlGaN/GaN high-electron-mobility transistors (HEMTs). Eighteen pairs of dipole antennas with different center frequency from 0.24 to 7.4 THz are arrayed into a bow-tie pattern. The corresponding eighteen transistors have common a source and a drain but different gated channels coupled by the corresponding antennas. The photocurrents generated by each gated channel are combined in the drain as the output port. With incoherent terahertz radiation from a hot blackbody in a Fourier-transform spectrometer (FTS), the detector exhibits a continuous response spectrum from 0.2 to 2.0 THz at 298 K and from 0.2 to 4.0 THz at 77 K, respectively. The results agree well with simulations taking into account the silicon lens, antenna and blackbody radiation law. The sensitivity is characterized under coherent terahertz irradiation, the average noise-equivalent power (NEP) is about 188 / at 298 K and 19 / at 77 K from 0.2 to 1.1 THz, respectively. A maximum optical responsivity of 0.56 A/W and a minimum NEP of 7.0 / at 0.74 THz are achieved at 77 K. The blackbody response spectrum is divided by the blackbody radiation intensity to obtain a performance spectrum, which is calibrated by measuring coherence performance from 0.2 to 1.1 THz to evaluate detector performance at frequencies above 1.1 THz. At 298 K, the NEP is about 1.7 / at 2.0 THz. At 77 K, the NEP is about 3 / at 4.0 THz. For further improvements in sensitivity and bandwidth, high-bandwidth coupling components, smaller series resistance, smaller gate lengths and high-mobility materials need to be considered.

为了满足宽带和高灵敏度太赫兹探测器的需求，我们设计并验证了一种基于天线耦合的 AlGaN/GaN 高电子迁移率晶体管（HEMT）的宽带太赫兹探测器。18 对具有不同中心频率（从 0.24 到 7.4 THz）的偶极天线排列成蝴蝶结图案。相应的 18 个晶体管具有公共源极和漏极，但不同的栅极通道通过相应的天线耦合。每个栅极通道产生的光电流在漏极中作为输出端口组合。用傅里叶变换光谱仪（FTS）中的热黑体的非相干太赫兹辐射，探测器在 298 K 时分别在 0.2 到 2.0 THz 和 77 K 时在 0.2 到 4.0 THz 范围内显示连续响应光谱。结果与考虑硅透镜、天线和黑体辐射定律的模拟结果吻合较好。在相干太赫兹辐照下对灵敏度进行了表征，在 0.2 到 1.1 THz 范围内，平均噪声等效功率（NEP）在 298 K 时约为 188 / ，在 77 K 时约为 19 / 。在 77 K 时，在 0.74 THz 处获得了 0.56 A/W 的最大光响应率和 7.0 / 的最小 NEP。黑体响应光谱通过黑体辐射强度进行划分，以获得性能光谱，该光谱通过测量 0.2 到 1.1 THz 范围内的相干性能进行校准，以评估频率高于 1.1 THz 时的探测器性能。在 298 K 时，NEP 约为 2.0 THz 时的 1.7 / 。在 77 K 时，NEP 约为 4.0 THz 时的 3 / 。为了进一步提高灵敏度和带宽，需要考虑高带宽耦合元件、更小的串联电阻、更小的栅长和高迁移率材料。