Trap Assisted Bulk Silicon Photodetector with High Photoconductive Gain, Low Noise, and Fast Response by Ag Hyperdoping

Abstract

suffer from high cost, complementary metal-oxide-semiconductor (CMOS) incompatibility, and not being environment friendly. Design and fabrication of a low-cost and CMOS-compatible siliconbased photoconductor is always urgent for current and future optoelectronics application. Unfortunately, silicon-based photoconductors usually exhibit a certain degree of latency in the photocurrent fluctuation when light is on or off, usually around 1-10 ms. [13][14][15] Meanwhile, they also suffer from a very large dark current, due to the extrinsic charge injection under reverse bias voltage, which causes the shot noise, weakens the detection sensitivity, and increases the power wastage. [12,16] Recently, the chalcogen (S, Se, and Te) and some transition metals (Au, Ti, etc.) hyperdoping in silicon has been recognized to be a potential for the fabrication of silicon-based photodetectors. [3,4,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] It has been reported that the chalcogen hyperdoped silicon photodetector can exhibit a high photoconductive gain under illumination while preserve a diode-rectifying effect in the dark. [24][25][26][29][30][31] This provides a novel path to the silicon-based photoconductors with a low noise and a high detect sensitivity. It was reported that the charge carrier trap states may play an essential role in the enhanced photoresponse. [24] However, this phenomenon has not yet been reported in the transition metal hyperdoped silicon photodetectors, and the related mechanism and its operating principle for this type of silicon photoconductors are still open for question. Meanwhile, theoretical calculations suggest that chalcogen dopant hyperdoping in silicon is not the best choice for the fabrication of photoconductors. [32,33] The silver (Ag) hyperdoping in silicon has a relatively higher optical figure of merit (v, defined by the ratio of carrier lifetime to transmit time), which is expected to have stronger potential in the optoelectronic application. [32,33] However, this interestingly theoretical prediction is still lack of the verification of related experiments.Here, we report a highly sensitive and room-temperature operated bulk silicon photodetector based on Ag hyperdoped silicon (Si:Ag). The Si:Ag samples were prepared by thermal evaporation deposition of Ag films and subsequent femtosecond pulsed laser melting (fs-PLM). A large density of Silicon-based photoconductors, with their low cost, high sensitivity, and complementary metal-oxide-semiconductor (CMOS) compatibility, have great potential for high-resolution imaging, light-activated switching, and singlephoton counting. However, they usually suffer from a large dark leakage current and a long response time, which greatly limits their applications. Here, a highperformance bulk silicon photodetector is fabricated working at room temperature with a broad spectral response range from 300 to 1200 nm through silver (Ag) hyperdoping. The detector shows a low dark current of 3.8 × 10 −7 A cm −2 and a high external quantum efficie...

Advances in perovskite photodetectors

“…[5][6][7] In the past, various types of semiconductor optoelectronic materials have been reported to fabricate photodetectors, such as silicon, the III-V compound semiconductors, organic polymer, and colloidal quantum dots (QDs). [8][9][10][11] However, the manufacturing process of traditional inorganic semiconductor materials with high temperature is always complicated and expensive. The polymer and colloidal QDs materials with unmanageable synthesis always suffer from insufficient absorption and short carrier lifetime, which lead to severe limitation in practical applications.…”

Solution-processed near-infrared Cu(In,Ga)(S,Se)2 photodetectors with enhanced chalcopyrite crystallization and bandgap grading structure via potassium incorporation

“…2 e). Therefore, injected holes are effectively transported to the electrode, producing EQE more than 100% in K-solCIGS devices at the low power light 35 – 39 . In contrast, under illumination at high power, the light absorption occurs in the quasi-neutral region beyond the W SCR region.…”

Role of layer thickness and field-effect mobility on photoresponsivity of indium selenide (InSe)-based phototransistors

“…Thus, the internal gain depends on mobility as Gint = µFE×VDS×ηsep×τlifetime/L 2 . For lower illumination intensities, the external quantum efficiency (EQE) approaches internal gain (Gint) [39]. Thus, at lower effective powers, internal gain can also be determined by Gint = R×h×c/(e×λ) where h is the planks constant, c is the speed of light, e is the charge of an electron and λ is the wavelength of illumination light.…”