Wafer‐Scale Growth of Vertical‐Structured SnSe₂ Nanosheets for Highly Sensitive, Fast‐Response UV–Vis–NIR Broadband Photodetectors

Abstract

Owing to the strong light–matter interactions, 2D semiconducting thin films have shown their great potential in the development of high‐performance ultraviolet–visible–near infrared (UV–Vis–NIR) broadband photodetectors (PDs). However, the planar 2D semiconducting thin films via conventional growth method are often in the form of isolated flakes and/or suffering from low absorption efficiency of light, which hinders the UV–Vis–NIR optoelectronics from widespread applications. Herein are reported high‐performance nonplanar UV–Vis–NIR broadband PD arrays, based on wafer‐scale, vertical‐structured SnSe2 nanosheet arrays (NSAs) via low‐temperature molecular beam epitaxy method. The vertical‐structured SnSe2 NSAs possess light absorption efficiency of >90% covering the wave range from 340 to 650 nm. Benefiting from the excellent light trapping ability and uniformity of waferscaled SnSe2 NSAs as well as relatively short channel, the broadband PD arrays exhibit superior comprehensive performance. They achieve a high responsivity of 31.94 A W‐1, fast speed (≈63 μs), and high uniformity. In addition, the responsivity of the broadband PD arrays is further improved via Zn‐doping technique.

An Ultrahigh‐Contrast Violet Phosphorus Van der Waals Phototransistor

“…The high ON/OFF ratio facilitates this process and, as a result, the letters "SJTU" is successfully demonstrated using green (𝜆 = 532 nm, Figure 4d) and red (𝜆 = 727 nm, Figure 4e) light illumination at varying incident powers. Compared with similar array-level image-sensing devices based on BP, [29] Bi 2 O 2 Se, [30,31] MoS 2 , [32,33] and SnSe 2 , [34] the imaging contrast of the VP photodetector array is improved by 2-4 orders of magnitude. The successful array-level image-sensing demonstrations imply violet phosphorus is a promising candidate to fabricate the photodetector array with CMOS processing compatibility and realize low background noise and high-contrast target object imaging, trajectory tracking, etc.…”

Fast near-infrared photodetectors from p-type SnSe nanoribbons

“…Currently, a variety of growth methods for low-dimensional nanomaterials have been reported, such as self-assembly [14], chemical vapor deposition [15], physical vapor deposition [16], and solution-liquid-solid methods [17]. Among these nanomaterials grown by various methods, IV-VI semiconductor nanomaterials with narrow band gaps, such as SnS [18,19], SnS 2 [20], SnSe 2 [21], and PbS [22], have been demonstrated promising in the field of optoelectronics and photonics applications.…”

Piezo-phototronic effect regulated broadband photoresponse of a-Ga2O3/ZnO heterojunction

“…6,[16][17][18] Recently, broadband photodetectors with a wide spectral photoresponse, as essential components of the modern integrated and miniaturized electronics industry, have received widespread attention for many technological applications, such as in imaging, optical communications, remote sensing, photoelectric memory, environment monitoring and military surveillance. [19][20][21][22] Moreover, the flexible characteristics of these device will expand their potential uses in human-machine interfaces and wearable applications. 23 It has been reported that crystalline disorder and oxygen vacancies in a-Ga 2 O 3 lead to a relatively narrow bandgap and a broad light absorption range.…”