Highly Photosensitive Lead Sulfide Thin Films Grown by H₂S Free MOCVD Using a Single Source Metal‐Organic Precursor

Abstract

High‐quality lead sulfide (PbS) films are deposited on selected substrate chemistries by an H2S‐free metal‐organic chemical vapor deposition (MOCVD) process using a single‐source metal‐organic complex (Pb(dmampS)2). The complex is synthesized via a salt metathesis reaction between PbCl2 and lithium 1‐(dimethylamino)‐2‐methylpropane‐2‐thiolate (Li(dmampS)) in diethyl ether. Subsequent film deposition is conducted by a simple thermolysis process in the absence of H2S, yet chemical and structural analysis confirm chemically stoichiometric and homogenous films. Mechanistic studies with electron impact mass spectroscopy (EIMS) and gas chromatography mass spectroscopy (GCMS) suggest the selective cleavage of C−S bonds in the complex as the reason for the facile PbS formation with negligible impurity incorporation. The high crystallinity, low hole concentrations, and charge transport properties comparable and in many cases superior to films produced by atomic layer deposition (ALD) testify to the quality of the films. Lastly, rigid and flexible photodetectors fabricated with the PbS films exhibit considerably high photocurrents, reliable switching characteristics, and high sensitivity over a broad spectral bandwidth, highlighting the potential for realizing practical broadband photodetectors.

Structural Instability Stimulated Heteroatoms Co‐Doping of 2D Quaternary Semiconductor for Optoelectronic Applications

“…Figure 4c-e A linear correlation between the photocurrent and the applied bias voltage was observed with both lasers, which was attributed to the increase in the carrier drift velocity. [11,36] The ReMoOSbased photodetector exhibited a significantly enhanced photocurrent and rapid response/recovery times, as compared with those of the MoS 2 -and ReO 3 -MoS 2 -based photodetectors, as shown in Figure 4c-e. The photocurrent of ReMoOS at 532 nm was The enhanced photoelectrical performance and reduced response/recovery times in the quaternary semiconductor systems can be attributed to the following effects: i) Improved crystalline and enhanced suppression of recombination achieved by anchoring heteroatoms in the vacancy sites.…”

“…The insets of Figure 4c–e show the regions of the response time (90% of maximum photocurrent) and recovery time (10% minimum photocurrent) for the various photodetectors at 20 V. A linear correlation between the photocurrent and the applied bias voltage was observed with both lasers, which was attributed to the increase in the carrier drift velocity. [ 11,36 ] The ReMoOS‐based photodetector exhibited a significantly enhanced photocurrent and rapid response/recovery times, as compared with those of the MoS 2 ‐ and ReO 3 ‐MoS 2 ‐based photodetectors, as shown in Figure 4c–e. The photocurrent of ReMoOS at 532 nm was 2367 nA at 20 V, which was 126.7‐ and 24.74‐fold higher than those of pristine MoS 2 (18.68 nA) and ReO 3 ‐MoS 2 (95.64 nA), respectively.…”