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Suppressed light-induced phase transition of CsPbBr2I: Strategies, progress and applications in the photovoltaic field 234
Hushan Zhang, Zhiwen Jin
2021, 42(7): 071901. doi: 10.1088/1674-4926/42/7/071901

The rapid rise in the power conversion efficiency (PCE) of CsPbBr2I-based perovskite solar cells (PSCs), from 4.7% in 2016 to 11.08% in 2020, render it a promising material for use in photovoltaic devices. However, the phase stability and current hysteresis caused by photo-induced phase segregation in CsPbBr2I represent major obstacles to further improvements in the PCE for such devices. In this review, we describe the basic structure and optical properties of CsPbBr2I, and systematically elaborate on the mechanism of the phase transition. We then discuss the strategies in progress to suppress phase transition in CsPbBr2I, and their potential application in the photovoltaic field. Finally, challenges and application prospects for CsPbBr2I PSCs are summarized in the final section of this article.

Finite element analysis on factors influencing the clamping force in an electrostatic chuck 232
Xingkuo Wang, Jia Cheng, Kesheng Wang, Yiyong Yang, Yuchun Sun, Minglu Cao, Linhong Ji
2014, 35(9): 094011. doi: 10.1088/1674-4926/35/9/094011

As one of the core components of IC manufacturing equipment, the electrostatic chuck (ESC) has been widely applied in semiconductor processing such as etching, PVD and CVD. The clamping force of the ESC is one of the most important technical indicators. A multi-physics simulation software COMSOL is used to analyze the factors influencing the clamping force. The curves between the clamping force and the main parameters such as DC voltage, electrode thickness, electrode radius, dielectric thickness and helium gap are obtained. Moreover, the effects of these factors on the clamping force are investigated by means of orthogonal experiments. The results show that the factors can be ranked in order of voltage, electrode radius, helium gap and dielectric thickness according to their importance, which may offer certain reference for the design of ESCs.

An implantable neurostimulator with an integrated high-voltage inductive power-recovery frontend 224
Yuan Wang, Xu Zhang, Ming Liu, Peng Li, Hongda Chen
2014, 35(10): 105012. doi: 10.1088/1674-4926/35/10/105012

This paper present a highly-integrated neurostimulator with an on-chip inductive power-recovery frontend and high-voltage stimulus generator. In particular, the power-recovery frontend includes a high-voltage full-wave rectifier (up to 100 V AC input), high-voltage series regulators (24/5 V outputs) and a linear regulator (1.8/3.3 V output) with bandgap voltage reference. With the high voltage output of the series regulator, the proposed neurostimulator could deliver a considerably large current in high electrode-tissue contact impedance. This neurostimulator has been fabricated in a CSMC 1 μm 5/40/700 V BCD process and the total silicon area including pads is 5.8 mm2. Preliminary tests are successful as the neurostimulator shows good stability under a 13.56 MHz AC supply. Compared to previously reported works, our design has advantages of a wide induced voltage range (26-100 V), high output voltage (up to 24 V) and high-level integration, which are suitable for implantable neurostimulators.

A reconfigurable 256 × 256 image sensor controller that is compatible for depth measurement 205
Zhe Chen, Shan Di, Cong Shi, Liyuan Liu, Nanjian Wu
2014, 35(10): 105007. doi: 10.1088/1674-4926/35/10/105007

This paper presents an image sensor controller that is compatible for depth measurement, which is based on the continuous-wave modulation time-of-flight technology. The image sensor controller is utilized to generate reconfigurable control signals for a 256×256 high speed CMOS image sensor with a conventional image sensing mode and a depth measurement mode. The image sensor controller generates control signals for the pixel array to realize the rolling exposure and the correlated double sampling functions. An refined circuit design technique in the logic level is presented to reduce chip area and power consumption. The chip, with a size of 700×3380 μm2, is fabricated in a standard 0.18 μm CMOS image sensor process. The power consumption estimated by the synthesis tool is 65 mW under a 1.8 V supply voltage and a 100 MHz clock frequency. Our test results show that the image sensor controller functions properly.

The effects of electron irradiation on the optical properties of the organic semiconductor polypyrrole 199
J. V. Thombare, M. C. Rath, S. H. Han, V. J. Fulari
2013, 34(9): 093001. doi: 10.1088/1674-4926/34/9/093001

The optical properties of polypyrrole (Ppy) thin films upon 2 MeV electron beam irradiation changes with different doses. The induced changes in the optical properties for Ppy thin films were studied in the visible range 300 to 800 nm at room temperature. The optical band gap of the pristine Ppy was found to be 2.19 eV and it decreases up to 1.97 eV for a 50 kGy dose of 2 MeV electron beam. The refractive index dispersion of the samples obeys the single oscillator model. The obtained results suggest that electron beam irradiation changes the optical parameters of Ppy thin films.

A wide-bandgap copolymer donor with a 5-methyl-4H-dithieno[3,2-e:2',3'-g]isoindole-4,6(5H)-dione unit 163
Anxin Sun, Jingui Xu, Guanhua Zong, Zuo Xiao, Yong Hua, Bin Zhang, Liming Ding
2021, 42(10): 100502. doi: 10.1088/1674-4926/42/10/100502

Research on process-induced effect in 14-nm FinFET gate formation and digital unit optimization design 131
Yafen Yang, Hang Xu, Tianyang Feng, Jianbin Guo, David Wei Zhang
2024, 45(12): 122303. doi: 10.1088/1674-4926/24080032

The advanced fin-shaped field-effect transistor (FinFET) technology offers higher integration density and stronger channel control capabilities, however, more complex process effects are also introduced which have significant influence on device performance. To address these issues, we complete a design-technology co-optimization (DTCO) focused on FinFET, including both process-induced effect during gate formation and corresponding digital unit optimization design. The 14 nm FinFET complementary metal oxide semiconductor (CMOS) technology is used to illustrate the sensitivity of transistor performance to process-induced effect, specifically the poly pitch effect (PPE) and cut poly effect (CPE). Predictive technology computer aided design (TCAD) simulations have been carried out to evaluate the transistor performance in advance. Based on the results, optimizations in digital unit design is proposed. Fall delay of the digital unit inverter is decreased by 0.7%, and the rise delay is decreased by 2.1%. For multiple selector (MUX2NV), the delay decreases by 4.64% for rise and 3.56% for drop, respectively.

Spray pyrolysis of tin selenide thin-film semiconductors:the effect of selenium concentration on the properties of the thin films 130
M. R. Fadavieslam, M. M. Bagheri-Mohagheghi
2013, 34(8): 082001. doi: 10.1088/1674-4926/34/8/082001

Thin films of tin selenide (SnxSey) with an atomic ratio of $r=\left[\frac{y}{x}\right]=0.5$, 1 and 1.5 were prepared on a glass substrate at T=470℃ using a spray pyrolysis technique. The initial materials for the preparation of the thin films were an alcoholic solution consisting of tin chloride (SnCl4· 5H2O) and selenide acide (H2SeO3). The prepared thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy, scanning tunneling microscopy, scanning helium ion microscopy, and UV-vis spectroscopy. The photoconductivity and thermoelectric effects of the SnxSey thin films were then studied. The SnxSey thin films had a polycrystalline structure with an almost uniform surface and cluster type growth. The increasing atomic ratio of r in the films, the optical gap, photosensitivity and Seebeck coefficient were changed from 1.6 to 1.37 eV, 0.01 to 0.31 and -26.2 to -42.7 mV/K (at T=350 K), respectively. In addition, the XRD patterns indicated intensity peaks in r=1 that corresponded to the increase in the SnSe and SnSe2 phases.

A review of ToF-based LiDAR 125
Jie Ma, Shenglong Zhuo, Lei Qiu, Yuzhu Gao, Yifan Wu, Ming Zhong, Rui Bai, Miao Sun, Patrick Yin Chiang
2024, 45(10): 101201. doi: 10.1088/1674-4926/24040015

In recent years, propelled by the rapid iterative advancements in digital imaging technology and the semiconductor industry, encompassing microelectronic design, manufacturing, packaging, and testing, time-of-flight (ToF)-based imaging systems for acquiring depth information have garnered considerable attention from both academia and industry. This technology has emerged as a focal point of research within the realm of 3D imaging. Owing to its relatively straightforward principles and exceptional performance, ToF technology finds extensive applications across various domains including human−computer interaction, autonomous driving, industrial inspection, medical and healthcare, augmented reality, smart homes, and 3D reconstruction, among others. Notably, the increasing maturity of ToF-based LiDAR systems is evident in current developments. This paper comprehensively reviews the fundamental principles of ToF technology and LiDAR systems, alongside recent research advancements. It elucidates the innovative aspects and technical challenges encountered in both transmitter (TX) and receiver (RX), providing detailed discussions on corresponding solutions. Furthermore, the paper explores prospective avenues for future research, offering valuable insights for subsequent investigations.

Structural and optoelectronic properties of sprayed Sb:SnO2 thin films: Effects of substrate temperature and nozzle-to-substrate distance 123
A. R. Babar, S. S. Shinde, A. V. Moholkar, C. H. Bhosale, K. Y. Rajpure
2011, 32(10): 102001. doi: 10.1088/1674-4926/32/10/102001

The influence of substrate temperature and nozzle-to-substrate distance (NSD) on the structural, morphological, optical and electrical properties of Sb:SnO2 thin films prepared by chemical spray pyrolysis has been analyzed. The structural, morphological, optical and electrical properties were characterized by using XRD, SEM, UV-visible spectrophotometry and Hall effect measurement techniques. It was seen that the films are polycrystalline, having a tetragonal crystal structure with strong orientation along the (200) reflection. The pyramidal crystallites formed due to coalescence were observed from SEM images. The values of highest conductivity, optical transmittance and figure of merit of about 1449 (Ω·cm)-1, 70 % and 5.2 × 10-3 □/Ω, respectively, were observed for a typical film deposited using optimal conditions (substrate temperature D 500 ℃ and NSD D 30 cm).