Self-powered reduced-dimensionality perovskite photodiodes with controlled crystalline phase and improved stability

Lim, Ju Won,Wang, Huan,Choi, Chi Hun,Kwon, Hannah,Quan, Li Na,Park, Won-Tae,Noh, Yong-Young,Kim, Dong Ha Elsevier 2019 Nano energy Vol.57 No.-

<P><B>Abstract</B></P> <P>In this work, we developed the perovskite photodiodes based on the dimensionality-reduced quasi two-dimensional (Q-2D) photoactive layer structure by incorporating phenylethylammonium iodide (PEAI) into methylammonium lead iodide (MAPbI<SUB>3</SUB>), which effectively enhanced both the crystalline phase and the ambient stability of the perovskite. The Q-2D perovskite photodiode exhibited a dark current of 1.76 × 10<SUP>−7</SUP> A/cm<SUP>2</SUP>, resulting in the detectivity (D*) of 2.20 × 10<SUP>12</SUP> J and responsivity of 0.53 A/W, which is among the highest performance levels without the voltage bias (0 V) due to the systematically optimized perovskite phase resulting in the reduced leakage current. In addition, the current density of Q-2D perovskite photodiode maintained 76% of the initial level current density even after 80 days in the ambient condition, compared to 15% of 3D perovskite photodiode control sample. Such superior performance and stability were mainly attributed to the enhanced degree of crystallization of the Q-2D perovskites, which was confirmed by X-ray diffraction and grazing incidence wide-angle X-ray scattering (GIWAXS) measurement. Also, the improved stability of Q-2D perovskite films was confirmed by both lifetime test and atomic force microscopy studies where the negligible number of pinholes was observed in the quasi-2D perovskite films while considerable deformations were found in the 3D perovskites photodiode. Our study suggests a simple and robust protocol for the development of stable and high-performance perovskite photodetectors via dimensional and constitutional optimization of conventional perovskites for the practical usage of perovskite in the photodiode applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The Q-2D perovskite photodiode exhibited the D* of 2.20 × 10<SUP>12</SUP> J and R of 0.53 A/W without the voltage bias (0 V). </LI> <LI> The current density of Q-2D perovskite photodiode maintained 76 % of the initial level while 15 % for the 3D one. </LI> <LI> Grazing incidence wide-angle X-ray scattering (GIWAXS) analysis revealed the origin of the stability improvement. </LI> <LI> Quasi-2D perovskite materials can be promising candidates for stable, tunable and flexible optoelectronic applications. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Dimensionality-controlled perovskite photodiodes with improved stability were systematically fabricated while retaining the comparable electrical performance of conventional three-dimensional perovskites. The quasi-2D perovskite photodetector exhibited an improved detectivity of 2.20 × 10<SUP>12</SUP> J performance and maintained 76% of initial level while the performance of three-dimensional perovskite photodetector remained only 15% after 80 days. Our study suggests a facile solution for the poor stability of the three-dimensional perovskite, with a potential for the development of highly-stable perovskite optoelectronics.</P> <P>[DISPLAY OMISSION]</P>

Temperature, Current, and Voltage Dependences of Junction Failure in PIN Photodiodes

Sahnggi Park,심은덕,박정우,백용순,Jae-Sik Sim,Hyun-Woo Song,Su Hwan Oh 한국전자통신연구원 2006 ETRI Journal Vol.28 No.5

A PIN photodiode having a low dark current of 1.35 nA and a high external quantum efficiency of 95.3% fabricated for a passive optical network receiver. As the current was increased under a high voltage of 38 V and a temperature of 190°C, it was observed that there is a threshold current at 11 mA which induces a junction failure. Experimental data suggest that the junction failure occurs due to the crystal breaking at the end facet as a result of thermal heat or energetic carriers. This threshold behavior of junction failure is a valuable observation for the safe treatment of photodiodes. As long as the current is limited below the threshold currents, we have not observed failure events of our photodiodes.

Colloidal Quantum Dot Photodiodes with Ligand-dependable and Photolithographic Patterning Technique

정신영,차순규,한일기 한국진공학회 2019 Applied Science and Convergence Technology Vol.28 No.3

We patterned a quantum dot (QD) layer via photolithography and fabricated a QD photodiode using an inverted QD-light emitting diode (LED) structure. It shows behavior similar to normal photodiodes in terms of photoresponse. However, the dark current was reduced by 1/10 and the photocurrent increased 10 times in comparison with unpatterned QD photodiodes. This study is beneficial for creating multicolor QD sensors and simultaneously integrating LEDs and photosensors on the same structure. It means that the sensor works while blinking time of LED and it could be applied to advanced display technique.

Colloidal Quantum Dot Photodiodes with Ligand-dependable and Photolithographic Patterning Technique

ShinYoung Jeong,Soon-kyu Cha,Il Ki Han 한국진공학회(ASCT) 2019 Applied Science and Convergence Technology Vol.28 No.3

We patterned a quantum dot (QD) layer via photolithography and fabricated a QD photodiode using an inverted QD-light emitting diode (LED) structure. It shows behavior similar to normal photodiodes in terms of photoresponse. However, the dark current was reduced by 1/10 and the photocurrent increased 10 times in comparison with unpatterned QD photodiodes. This study is beneficial for creating multicolor QD sensors and simultaneously integrating LEDs and photosensors on the same structure. It means that the sensor works while blinking time of LED and it could be applied to advanced display technique.

CMOS Image Sensor with Dual-Sensitivity Photodiodes and Switching Circuitfor Wide Dynamic Range Operation

Lee, Jimin,Choi, Byoung-Soo,Bae, Myunghan,Kim, Sang-Hwan,Oh, Chang-Woo,Shin, Jang-Kyoo The Korean Sensors Society 2017 센서학회지 Vol.26 No.4

Conventional CMOS image sensors (CISs) have a trade-off relationship between dynamic range and sensitivity. In addition, their sensitivity is determined by the photodiode capacitance. In this paper, CISs that consist of dual-sensitivity photodiodes in a unit pixel are proposed for achieving wide dynamic ranges. In the proposed CIS, signal charges are generated in the dual photodiodes during integration, and these generated signal charges are accumulated in the floating-diffusion node. The signal charges generated in the high-sensitivity photodiodes are transferred to the input of the comparator through an additional source follower, and the signal voltages converted by the source follower are compared with a reference voltage in the comparator. The output voltage of the comparator determines which photodiode is selected. Therefore, the proposed CIS composed of dual-sensitivity photodiodes extends the dynamic range according to the intensity of light. A $94{\times}150$ pixel array image sensor was designed using a conventional $0.18{\mu}m$ CMOS process and its performance was simulated.

Role of p-NiO electron blocking layers in fabrication of (P-N):ZnO/Al:ZnO UV photodiodes

R. Amiruddin,M.C. Santhosh Kumar 한국물리학회 2016 Current Applied Physics Vol.16 No.9

We report the fabrication and characterization of ZnO-based UV photodiodes with p-NiO as an intermediate electron blocking layer (EBL). The n-ZnO and p-ZnO layers are deposited by automated spray pyrolysis technique and NiO layers by r.f.magnetron sputtering. For the realization of p-ZnO, dual acceptor method has been adopted by doping equimolar concentration of group-V elements P and N (0.75 at%) simultaneously in ZnO. The formation of p-type characteristics in ZnO is confirmed by Hall measurement and X-ray photoelectron spectroscopy (XPS) analysis. The n-ZnO is doped with Al (3 at%) in order to improve the electrical properties. The properties of sputtered NiO layers have been investigated under three different deposition temperatures of 300 C, 350 C and 400 C. By analyzing structural and electrical properties, it is revealed that NiO deposited at 350 C possess better crystallinity and electrical properties. The optimum p-ZnO and n-ZnO layers are stacked upon ITO substrates to form ZnO-based p-n junctions. The effect of addition of NiO as an electron blocking layer (EBL) between the p-n junctions is investigated by analyzing the current density-voltage (J-V) and UV photoresponse properties. The fabricated ZnO-based UV photodiodes with NiO EBL exhibits a high photoresponsivity (R) value of 5.53 A/ W with external quantum efficiency (EQE) value of 1.87 103%.

Photoresponse of n-ZnO/p-Si photodiodes to violet-green bandwidth light caused by defect states

Cho, Seong Gook,Lee, Dong Uk,Kim, Eun Kyu Elsevier 2013 THIN SOLID FILMS - Vol.545 No.-

<P><B>Abstract</B></P> <P>We fabricated n-ZnO/p-Si photodiodes by ultra-high vacuum sputtering that were highly responsive to violet-green light illumination at low operating voltages. Under illumination with light at 420nm, the maximum photoresponsivity of the photodiodes was about 0.55A/W at −8V. As the ZnO film thickness increased from 150nm to 500nm, the photoresponsivity of the diodes to the wavelength range of 370–560nm increased markedly, while the absorption bandwidth decreased. In particular, a slow photo-response was observed under light between the wavelengths of 540–560nm. We speculate that the high photoresponsivity and slow photoresponse of the synthesized diodes are due to shallow and deep acceptor states originating from zinc vacancy defects in the ZnO thin film, respectively.</P> <P><B>Highlights</B></P> <P> <UL> <LI> n-ZnO/p-Si showed high photoresponse under violet-green lights at low voltages. </LI> <LI> Photoresponsivity of n-ZnO/p-Si photodiodes was reaching up to 0.55A/W at −8V. </LI> <LI> Zinc vacancy affects the photoresponsivity in the 370–560nm wavelength range. </LI> <LI> Slow photoresponse was observed under the light with wavelengths of 540–560nm. </LI> </UL> </P>

Single-Step Metal-Organic Vapor-Phase Diffusion for Low-Dark-Current Planar-Type Avalanche Photodiodes

전동환,Hae Yong Jeong,Youngjo Kim,Chan-Soo Shin,Kyung Ho Park,Won-Kyu Park,Min-Su Kim,Sangin Kim,Sang Wook Han,Sung Moon 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.8

In this paper, a p-type diffusion process based literally on single-step metal-organic vapor-phase diffusion (MOVPD) employing diethyl zinc as the diffusion source in combination with the recessetching technique is developed to improve the dark-current characteristics of planar-type avalanche photodiodes (APDs). The developed single-step MOVPD process exhibits on excellent linear relationship between the diffusion depth and the square root of the diffusion time, which mainly results from maintaining constant source diffusion. The single-step MOVPD process without any additional thermal activation process achieves a surface doping concentration of 1.9 × 1018 cm−3, which is sufficient to form ohmic contact. The measured diffusion profiles of the APDs clearly reveal the presence of a two-dimensional diffusion front formed by the recess-etched and guard-ring regions. The impact of this p-type diffusion process on the performance of the APD devices has also been demonstrated by exhibiting improved dark-current characteristics for the fabricated APDs.

Highly flexible and solution-processed organic photodiodes and their application to optical luminescent oxygen sensors

Lim, Chang-Jin,Kim, Jin-Hoon,Park, Jin-Woo ELSEVIER 2019 ORGANIC ELECTRONICS Vol.65 No.-

<P><B>Abstract</B></P> <P>We present a solution-processed flexible organic photodiode (f-OPD) with a bulk heterojunction (BHJ) structure based on a blend of poly (3-hexylthiophene-2,5-diyl) and 1-(3-methoxycarbonyl) propyl-1-phenyl[6,6]C<SUB>61</SUB> (P3HT:PCBM). We used Cs<SUB>2</SUB>CO<SUB>3</SUB>-doped polyethyleneimine ethoxylated (d-PEIE) as the electron transport layer (ETL) material, which significantly improved the electron injection properties of the f-OPD. Compared with f-OPDs with conventional ETL materials such as Cs<SUB>2</SUB>CO<SUB>3</SUB>, the external quantum efficiency (EQE) of the d-PEIE-based f-OPD was highly improved. Analytical results showed that the d-PEIE reduced the work function of the cathode, thereby facilitating the efficiency of electron injection from the active layer (AL) to the cathode of the f-OPD. In addition, after 10,000 cycles of tensile bending at a bending radius of 5 mm, the normalized <I>I</I> <SUB>D</SUB> variation (<I>I</I> <SUB>D</SUB>/<I>I</I> <SUB>D0</SUB>) in the d-PEIE-based f-OPD remained above 90%, indicating an excellent device bending stability. Finally, f-OPD-based luminescent oxygen (O<SUB>2</SUB>) sensors were successfully fabricated consisting of a photoluminescent O<SUB>2</SUB> sensing film, a light source, and an f-OPD. The O<SUB>2</SUB> sensors based on d-PEIE-based f-OPDs showed the highest photocurrent and O<SUB>2</SUB> sensitivity in relation to the O<SUB>2</SUB> concentration compared with O<SUB>2</SUB> sensors based on f-OPDs with conventional ETL materials.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The solution processed P3HT:PCBM based flexible OPDs (f-OPD) by Cs<SUB>2</SUB>CO<SUB>3</SUB>-doped polyethyleneimine ethoxylated (d-PEIE) as the ETL material showed significantly improved optoelectronic and mechanical properties. </LI> <LI> The d-PEIE based f-OPD reduced the work function of cathode facilitating the efficient electron injection from the active layer to the cathode of the f-OPDs. </LI> <LI> The d-PEIE enhanced the adhesion between the AL and cathode, which improved the mechanical stability of the f-OPDs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Optimization of charge and multiplication layers of 20-Gbps InGaAs/InAlAs avalanche photodiode

Sim, Jae-Sik,Kim, Kisoo,Song, Minje,Kim, Sungil,Song, Minhyup Electronics and Telecommunications Research Instit 2021 ETRI Journal Vol.43 No.5

We calculated the correlation between the doping concentration of the charge layer and the multiplication layer for separate absorption, grading, charge, and multiplication InGaAs/InAlAs avalanche photodiodes (APDs). For this purpose, a predictable program was developed according to the concentration and thickness of the charge layer and the multiplication layer. We also optimized the design, fabrication, and characteristics of an APD for 20 Gbps application. The punch-through voltage and breakdown voltage of the fabricated device were 10 V and 33 V, respectively, and it was confirmed that these almost matched the designed values. The 3-dB bandwidth of the APD was 10.4 GHz, and the bit rate was approximately 20.8 Gbps.