Infrared absorption and sub-bandgap photo-response of hyperdoped silicon by ion implantation and ultrafast laser melting

Local Coordination Modulates the Reflectivity of Liquefied Si–Ge Alloys

“…Si−Ge displayed intermediate features, showcasing both σ and s patterns (Figure 1g−i), but ELF planar averaged profiles in Figure S4, Supporting Information, signaled an electron density distribution similar to Si, with mean values of ∼0. 40. Summing up all these data, the increased coordination in the alloy stems from Si atoms in the first coordination shell prioritizing the formation of stronger, more directional σ bonds with neighboring Si atoms while also bonding with Ge atoms.…”

“…In these cases, the concentration of active dopants can reach atomic percentages as high as 5–10%, exceeding the crystal solubility limit. Ultradoping involves utilizing high doping concentrations to achieve superconductivity, whereas hyper-doping is linked to augmenting semiconductor bands to increase absorption coefficients and enhance plasmonic effects in the infrared region. − A successful completion of laser melting processes requires an in-depth design of experiments, often coupled to precise calculations. To this purpose, having an exhaustive comprehension of crystalline and liquid optical functions is essential.…”

Direct Fabrication of Te-Doped Black Si with an Enhanced Photoelectric Performance by Femtosecond Laser Irradiation under Water

“…Among them, Si exhibits excellent absorption and photoelectric performances associated with its low cost and wide use in multifunctional applications, which make it largely employed in the fields of photodetectors, − photodiodes, − and field emission devices. − However, Si displays certain limitations for infrared detection: it suffers a sharp absorption drop for incident light wavelengths longer than 1.1 μm due to its band gap and a high surface reflection, especially in visible range. Hence, the development of a Si-based infrared detector with ideal performances requires strategies aiming at both reducing its surface reflection in the visible and infrared spectral ranges and redshifting the absorption beyond its band gap. , …”

“…Hence, the development of a Si-based infrared detector with ideal performances requires strategies aiming at both reducing its surface reflection in the visible and infrared spectral ranges and redshifting the absorption beyond its band gap. 27,28 Antireflection coating 29 and black Si layer 22,27 have been proposed to improve Si-based detector performances through an enhancement of the surface antireflection properties. Compared with the conventional surface coating method, direct processing of a black Si layer stands out for its advantages in thermal stability and a simpler fabrication process.…”

Research progress of silicon nanowires array photodetectors

“…些特性使其成为制造各种半导体器件的关键元素 [1][2][3][4] 。硅具有较小的带隙、优越的光 捕获能力和快速的电荷传输能力，是构建宽带光电探测器的理想半导体。硅光电探 测器主要用于紫外到近红外(NIR)区域的光电探测 [5][6][7][8][9] 。然而，硅的间接带隙和有 限的吸收范围严重限制了硅基光电探测器的性能和应用。 为了改善硅基光电探测器的器件性能，人们对硅基进行纳米结构改造或构建互 补 半 导 体 异 质 结 [10][11][12][13][14] 。 在 这 些 方 案 中 ， 通 过 金 属 辅 助 化 学 蚀 刻 (Metal-Assisted Chemical Etching，MACE)制备的硅纳米结构(如硅纳米线或纳米柱等) ，因其拥有 卓越的收集光的能力及构建硅基/互补半导体异质结的潜力而备受关注。相关研究显 示，通过 MACE 制备的硅纳米结构可以有效拓宽硅基光电探测器的响应波段，在制 备柔性硅基光电探测器方面具有巨大的潜力 [15][16][17] [18] 指 出，超清洁硅片表面(即完全没有颗粒、有机杂质、金属杂质、天然氧化物、表面 微粗糙和吸附杂质的表面)对于实现超大规模集成生产至关重要。故而，对金属颗 粒的行为，特别是硅晶片表面上的贵金属离子和颗粒在湿式化学清洗溶液中的行为， 人们进行了广泛的研究，以了解金属沉积的基本机制以及如何将其从硅表面有效地 去除。 1994 年，Morinaga 等人 [19] 发现，贵金属阳离子可与硅的界面实现电荷转移，并 以金属状态沉积在硅表面，而在金属沉积物附近的硅被诱导氧化，被氧化的硅在稀 氢氟酸溶液中被溶解，从而导致硅表面出现凹坑和微观粗糙面。贵金属阳离子还原 是将硅的导带电子传导出去或者向硅的价带注入空穴来实现对硅的蚀刻。 图 1 给出了湿法蚀刻过程中硅表面上的铜沉积以及铜诱导蚀刻的机制。首先， 铜离子从硅衬底提取电子，并以金属铜的形式沉积在硅衬底上。由于铜原子核比硅 的电负性更高，因此会吸引硅中的电子，使铜带负电。附近的铜离子会沉积在铜核 周围，随着铜离子的持续沉积，铜核成为更大的颗粒，铜颗粒下方的硅表面释放出 与铜离子所需的电子，从而产生氧化硅 [19,20] 。在经过混有稀氢氟酸的过氧化氢溶液 处理后，硅表面会出现许多小孔；而对于没有金属颗粒的硅表面，并未观察到与初 始状态之间的明显差异。 图 1 金属辅助硅蚀刻(MACE)的微观解释 [19] Figure 1 Microscopic interpretation of Metal-Assisted Chemical Etching (MACE). [19] 1995 年，Morinaga 等人 [21] [22][23][24] 系统地研究了硅在含有氧化剂的氢氟酸水溶液中的…”