State Key Laboratory of Optoelectronic Materials and Technologies, Nanotechnology Research Center, School of Materials Science & Engineering, School of Physics, Sun Yat-sen University , Guangzhou 510275, Guangdong, P. R. China.
ACS Appl Mater Interfaces. 2016 Aug 17;8(32):20872-9. doi: 10.1021/acsami.6b06222. Epub 2016 Aug 4.
Photoelectric conversion is of great importance to extensive applications. However, thus far, photodetectors integrated with high responsivity, excellent detectivity, large phototo-dark current ratio, fast response speed, broad spectral range, and good stability are rarely achieved. Herein, we deposited large-scale and high-quality polycrystalline indium sesquitelluride (α-In2Te3) films via pulsed-laser deposition. Then, we demonstrated that the photodetectors made of the prepared α-In2Te3 films possess stable photoswitching behavior from 370 to 1064 nm and short response time better than ca. 15 ms. At a source-drain voltage of 5 V, the device achieves a high responsivity of 44 A/W, along with an outstanding detectivity of 6 × 10(12) cm H(1/2) W(-1) and an excellent sensitivity of 2.5 × 10(5) cm(2)/W. All of these figures-of-merit are the best among those of the reported α-In2Te3 photodetectors. In fact, they are comparable to the state-of-the-art commercial Si and Ge photodetectors. For the first time, we established the theoretical evidence that α-In2Te3 possesses a direct bandgap structure, which reasonably accounts for the superior photodetection performances above. Importantly, the device exhibits a good stability against the multiple photoswitching operation and ambient environment, along with no obvious voltage-scan hysteresis. These excellent figures-of-merit, together with the broad spectral range and good stability, underscore α-In2Te3 as a promising candidate material for next-generation photodetection.
光电转换对于广泛的应用具有重要意义。然而，迄今为止，很少有同时具备高响应率、优异的探测率、大光电暗电流比、快速响应速度、宽光谱范围和良好稳定性的光电探测器与之集成。在此，我们通过脉冲激光沉积法沉积了大面积高质量的多晶三碲化铟（α-In2Te3）薄膜。然后，我们证明了由所制备的α-In2Te3 薄膜制成的光电探测器在 370nm 至 1064nm 的范围内具有稳定的光电开关行为，并且响应时间短于约 15ms。在源漏电压为 5V 的情况下，该器件实现了 44A/W 的高光响应率，同时具有 6×10(12)cm H(1/2)W(-1)的出色探测率和 2.5×10(5)cm(2)/W 的优异灵敏度。所有这些性能指标都是已报道的α-In2Te3 光电探测器中的最佳值。事实上，它们可与最先进的商用 Si 和 Ge 光电探测器相媲美。我们首次建立了理论证据，证明α-In2Te3 具有直接带隙结构，这合理地解释了上述优越的光电探测性能。重要的是，该器件在多次光电开关操作和环境条件下表现出良好的稳定性，且没有明显的电压扫描滞后。这些优异的性能指标，加上宽光谱范围和良好的稳定性，突显了α-In2Te3 作为下一代光电探测器的有前途的候选材料。
