Ultrafast Response of Centimeter Scale Thin CsPbBr₃ Single Crystal Film Photodetector for Optical Communication

Abstract

Nevertheless, the inherent high trap density existed around the grain boundaries of PCF is ineluctable, [14][15][16] which restricts unobstructed carrier transport and boosts carrier recombination probability. Therefore, the performance enhancement of perovskite PCF has reached a bottleneck.Owing to its conspicuous crystallinity, high mobility, and low trap density, perovskite SCF within dozens of micrometers, is more attractive as light absorber for PDs than perovskite PCF. [17,18] Meanwhile, the larger area of perovskite crystal means a larger light receiving area. This makes large-area perovskite crystals are well received in the field of solar cells, integrated circuits, and light sensor arrays. [19][20][21] Unfortunately, due to the lack of immature technology for growing largesize thin SCF, reports about perovskite SCF PDs with ultra-fast response and high sensitivity remain scarce. Besides, the rotation hysteresis of organic components (FA, MA, etc) under an electric field and their instabilities against humidity and oxygen hinder the application of hybrid perovskite PDs with ultra-fast response. Fully inorganic cesium halide perovskites CsPbBr 3 (X = Br, I) demonstrate better stability and optoelectronic performances, and are therefore expected to obtain high stability and ultra-fast response optical communication devices. [22][23][24][25][26][27] Herein, we firstly report the growth of centimeter scale CsPbBr 3 SCFs with high quality and controllable thickness (40 µm) by an improved space-limited inverse temperature crystallization (ISLITC) procedure, in which the crystal growth process is controlled through variable heat areas. The MSM high-performance PD based on CsPbBr 3 SCF shows a fast response speed (500 kHz). Moreover, the use of our PD in an optical communication system is finally demonstrated. Results and DiscussionFigure 1a briefly shows the alterable heating area growth method of CsPbBr 3 SCF. Once stable nuclei are formed in a small heating region, the heating area is enlarged from 0.01 to 13 cm 2 to reduce the wafer growth rate and thus obtain high-quality and large-size wafers. To obtain large thin singleThe photodetector (PD) is the key component to realize efficient optoelectronic conversion signal in the visible light communication (VLC) system. The response speed directly determines the bandwidth of the whole system. Metal halide perovskite is a neotype of low-cost solution processing semiconductor, with strong optical absorption, low trap density, and high carrier mobility, thus has been widely explored in photoelectric detection applications. However, previously reported perovskite polycrystalline photodetectors exhibit limited response speed due to the existence of grain boundaries.Here, an improved confined space method is developed through adjusting the heating area to control nucleation, resulting in centimeter scale fully inorganic perovskite CsPbBr 3 thin single crystal films (SCFs) (<40 µm). The smooth surface and high crystallinity of CsPbBr 3 SCFs render admirable exciton lif...

Superior Performances of Self‐Driven Near‐Infrared Photodetectors Based on the SnTe:Si/Si Heterostructure Boosted by Bulk Photovoltaic Effect

“…Figure 4d presents the EQE of the SnTe:Si/Si and SnTe/Si devices measured at room temperature (300 K) as a function of light intensity for the 850 nm light. The EQE is defined as the ratio of the number of charge carriers collected by the device to the number of photons shining on the active area from the exterior laser: [ 36 ] $$\[ \begin{array}{*{20}{c}}{EQE\; = ({I_{{\rm{ph}}}}{\rm{/}}q){\rm{/}}\emptyset \; = ({I_{{\rm{ph}}}}{\rm{/}}q\;)\left( {h\nu {\rm{/}}{P_{{\rm{in}}}}} \right)}\end{array} \]$$where I ph, ∅, h , ν, and P in represent the photocurrent, number of incident photons, Planck's constant, frequency of the incident light, and incident light power on the active area of the device, [ 37 ] respectively. For the SnTe/Si device in Figure 4d, a maximum EQE of 75% is observed at a light intensity of 2.1 mW cm −2 .…”

“…Figure 4d presents the EQE of the SnTe:Si/Si and SnTe/Si devices measured at room temperature (300 K) as a function of light intensity for the 850 nm light. The EQE is defined as the ratio of the number of charge carriers collected by the device to the number of photons shining on the active area from the exterior laser: [36] EQE I q I q h P ν ( )…”

Advances in the Synthesis of Halide Perovskite Single Crystals for Optoelectronic Applications

“…When the thickness of the SC−TF was decreased from approximately 10 μm to several hundred nanometers, the device's minimum detectable power and internal gain increased by two and 4 for both 365 nm and white light, which is superior to previously reported CsPbBr 3 polycrystalline film and single crystal photodetectors. 167 As shown in Figure 19d, some 3D and ultrathin 2D layered perovskite crystals are promising materials for photodetection because of their improved stability and effectively suppressed ion migration. For example, Liu et al proposed an induced peripheral crystallization method for the growth of a 2D flexible single-crystalline membrane (SCM) with a thickness as low as 0.6 μm and an area of more than 2500 mm 2 .…”

Centimeter-size single crystals of 2D hybrid perovskites for shortwave light photodetection with a low detection limit

“…In recent years, organic-inorganic hybrid perovskites have become popular candidates for new optoelectronic materials due to their high carrier mobility, long carrier lifetime, high light absorption, low fabrication cost, and facile fabrication methods. [12][13][14][15][16][17][18][19] More interestingly, the layered two-dimensional (2D) organic-inorganic hybrid perovskite composed of an inorganic framework layer and staggered various organic cations greatly expands the perovskite material system. [20][21][22] Organic large cations as spacers can cut bulk perovskites into twodimensional materials, thereby forming unique quantum well structures and unique optoelectronic properties.…”