Low-cost photodetector architectures fabricated at room-temperature using nano-engineered silicon wafer and sol-gel TiO2 – based heterostructures

Abstract

In the last decades, significant research has been done on the nanocrystalline forms of titanium dioxide (TiO2). Amorphous TiO2 has not been studied intensively despite being significantly less expensive compared to crystalline TiO2. This study reveals significant improvement in UV-VIS photodetection properties from heterostructures fabricated in ambient environment using n-type silicon nanowire arrays and amorphous TiO2 sol-gel. Our ultra-low-cost UV-VIS photodetectors can cover a wide range of applications. We report fast rise/decay time constants of 0.23 ms/0.17 ms and high responsivity up-to 6.0 A/W in the UV and 25.0 A/W in the visible range under low (1 V) external bias. The large surface area due to the nanowire array architecture leads to 2 orders of magnitude enhancement in photo-response. Besides the final electrode deposition, the entire device fabrication is performed using low-cost, all solution-based methods in ambient conditions. These low-cost UV-Visible broadband photodetectors can potentially serve a wide range of applications.

High Performance Nanoplasmonic UV/VIS/NIR Photodetector Fabricated in Ambient Condition

“…The detectivity of these photodetector devices reaches up to 6.84 E 11 Jones, 2.16 E 12 Jones and 3.11 E 12 Jones in the near UV, VIS and NIR regions respectively. Simply adding these minute amounts of Ag nanoparticles extends the photodetection from UV-VIS region to UV-VIS-NIR region as compared to the pristine SiNWs/ amorphous TiO 2 devices as shown in our previous report 22 . Hence, the superior performance of the photodetector as compared to our previous report 22 can be attributed to the nanoplasmonic effect.…”

“…Simply adding these minute amounts of Ag nanoparticles extends the photodetection from UV-VIS region to UV-VIS-NIR region as compared to the pristine SiNWs/ amorphous TiO 2 devices as shown in our previous report 22 . Hence, the superior performance of the photodetector as compared to our previous report 22 can be attributed to the nanoplasmonic effect. The peak values of responsivity, EQE and detectivity at different wavelengths are illustrated in the Table 1.…”

“…The amorphous phase of TiO 2 has not been explored as extensively before, despite of having similar electronic properties as the crystalline phase 21 . In our previous studies, we have optimized similar behavior from amorphous TiO 2 based photodetectors in an energy e cient manner which is comparable to anatase TiO 2 based devices 22,23 .…”

Perovskite/Silicon‐Nanowire‐Based Hybrid Heterojunctions for Fast and Broadband Photodetectors

“…SiNW arrays were fabricated using immersion‐based galvanic displacement (GDM) chemistry directly on a commercial n‐type silicon wafer, according to previous reports. [ 19,44 ] An n‐type silicon wafer with a resistivity of 1–10 Ω cm (University Wafers) was cleaved into 4 cm 2 pieces using a carbide‐tip pen. The silicon pieces were then cleaned using ultrasonication in acetone and isopropyl alcohol (IPA) for 15 min each, rinsed with deionized water, and dried using a nitrogen air flow.…”

Broadband nanoplasmonic photodetector fabricated in ambient condition

“…The amorphous phase of TiO 2 has not been explored as extensively before, despite of having similar electronic properties as the crystalline phase [31,32]. We have previously optimized amorphous TiO 2 based photodetectors to have similar behavior, which is comparable to anatase TiO 2 based devices [33,34]. Making a heterojunction with amorphous TiO 2 in conjunction with plasmonic SiNWs extends its detection ability in a broadband wavelength range from UV to NIR.…”