P-type Silicon Substrates Research Articles

Heterostructural Nano-Scale Conductometric Sensing Devices to Improve Selective Gas Detection

Heterostructural Nano-Scale Conductometric Sensing Devices to Improve Selective Gas Detection

Optoelectronic Properties of Ce3+ Doped Silicon Oxide and Oxynitride Electroluminescent Devices

In this work, we propose a new type of silicon-based electroluminescent device. The thin film emitting layers of the device were deposited using Electron-Cyclotron-Resonance Plasma Enhanced Chemical-Vapor Deposition (ECR-PECVD) with in-situ Ce3+ doping on a P-type silicon substrate. Oxygen was gradually substituted by nitrogen to produce silicon oxynitride thin films with different layer compositions. Refractive indices extracted from variable-angle spectroscopic ellipsometry (VASE) measurements classified the thin films into two main groups, silicon oxide (SiOx) and silicon oxynitride (SiOxNy). The thin film composition was studied by Rutherford Backscattering Spectrometry (RBS), verifying the gradual increase in oxygen content. Photoluminescence (PL) spectroscopy of the emitting layer was obtained using a 375 nm laser as an excitation source. All samples were subjected to the post-deposition annealing treatment for 1 hour at different temperatures varying from 600 to 1200°C in 95% N2 and 5% H2 ambient gas environment, yielding considerably stronger blue PL emission than as-deposited ones. PL intensity of SiOx showed a sudden increase due to the formation of Ce2Si2O7 clusters when annealed at 1200°C. Internal Quantum Efficiency (IQE) and External Quantum Efficiency (EQE) were measured using an integrating sphere and a UV-Vis-NIR spectrometer. The optimum layer composition and annealing condition to produce SiOxNy thin films with maximized Ce3+ excitation efficiency were obtained. To further investigate the electrical performance of the produced samples, the thin films were coated with indium tin oxide (ITO) and aluminum (Al) on the top and bottom side of the thin film respectively. Current-Voltage (I-V) measurements showed improved charge injections in SiOxNy compared to SiOx, due to the reduction of the bandgap upon the incorporation of nitrogen.

Annealing Effect on Microstructure and ElectricalCharacteristics of n-ZnO/p-Si HetrojunctionDiode Fabricated by RF Sputtering Process

This article reports fabrication and microstructural characterization ofn-ZnO/p-Si heterojunction diode. Nanostructured Zinc Oxide (ZnO) thinfilm was deposited on p-type silicon (Si) and glass substrates using RFsputtering process for fabricating n-ZnO/p-Si heterojunction diode. Theeffect of annealing temperature on the structural and morphologicalproperties of ZnO thin films has been observed. After deposition,these films are annealed. Structural properties, surface morphologyand quality of thin film have been studied using XRD, AFM, FE-SEMand Energy Dispersive X-ray Spectroscope (EDX) measurements. XRDresults confirms the formation of ZnO. The crystallite size of ZnO filmswas increased by annealing it at 523 K. The average crystallite size ofas deposited nanostructured ZnO thin film was found to be 28 nm.The junction properties of n-ZnO/p-Si heterojunction diodes wereinvestigated using current–voltage measurements. The current wereanalyzed by sweeping the voltage from -6V to +6V and and the kneevoltage was found to be around 1.9V.

Effect of insulator layer thickness on electrical properties of Al/BiFeO3/ZrO2/p-Si for nonvolatile memory applications

BiFeO3 (BFO) and ZrO2 have been deposited on p-type (100) silicon substrate by sol-gel process and rf sputtering method, respectively. Metal-ferroelectric-insulator-semiconductor capacitor has been fabricated with 100 nm BFO and 10 nm ZrO2 shows maximum memory window of 1.54 V as compared to other fabricated capacitors with 5 and 15 nm insulating layer thickness. Improvement in current density has been also observed in different thickness of buffer layer of MFIS capacitors. The improved current density of order of 10-7 A/cm2 has been observed in MF(100nm)I(10nm)S structure. It has been also observed in MF(100nm)I(10nm)S structure that no charge value degrades up to 1011 iteration cycles.

Structural properties of TiN thin films prepared by RF reactive magnetron sputtering

In this present work, thin films of Amorphous Titanium Nitride (TiN) were deposited on suitably cleaned oxidized p-type silicon (SiO2) substrates with few nanometers in thickness by Radio Frequency (R.F.) reactive magnetron sputtering at room temperature. The structural and morphological changes of amorphous TiN thin films was investigated at three different gas ratios such as R[Ar/N2 = 1:1, 1:2 and 1:5] and corresponding films thickness were measured at 14 to 18 nm using profilometer. X-ray diffraction technique (XRD) was used to investigate the crystal structure of the as-deposited films, which confirms that amorphous films have been formed during the deposition. Field emission scanning electron microscopy (FE-SEM) analysis was employed to examine the surface morphology of the films which reveals that sputter deposited particles forming globular aggregates of ∼20 nm diameter; typical of magnetron sputtering deposition. The structural variation, crystallinity and defects of the thin films were studied by Raman spectroscopy.

The comparison of Co/hematoxylin/n-Si and Co/hematoxylin/p-Si devices as rectifier for a wide range temperature

We employed hematoxylin as interfacial layer between the n- and p-type silicon substrate and cobalt (Co) metallic contact to obtain and compare Co/hematoxylin/n-Si and Co/hematoxylin/p-Si devices for a wide range temperature via current-voltage (I–V) characteristics. Furthermore, we studied structural and morphological properties of the hematoxylin thin film by x-ray diffractometer (XRD) and scanning electron microscope (SEM). The temperature range was changed from 100 K to 460 K via 20 K interval for I–V measurements. The Co/hematoxylin/n-Si and Co/hematoxylin/p-Si devices exhibited excellent rectifying behaviors for low temperatures, but rectifying ratio (RR) values decreased with increasing temperature at ±1 V bias. In addition, the devices showed thermal sensor or detector behavior because current values increased with increasing temperature at reverse biases. The Co/hematoxylin/p-Si device has better stability than Co/hematoxylin/n-Si device at reverse biases for the same temperature values according to stop leakage current with increasing voltage. In addition, the diode parameters such as barrier height, ideality factor and series resistance as well as interface states density were extracted from the I–V measurements and compared in details for various techniques such as thermionic emission theory, Norde and Cheung methods. The diode parameters of the both devices were affected from the temperature changes. The Co/hematoxylin/n-Si and Co/hematoxylin/p-Si devices are good candidate for rectifying and thermal sensing applications.

Silver Nano-Dendrite-Plated Porous Silicon Substrates Formed by Single-Step Electrochemical Synthesis for Surface-Enhanced Raman Scattering

Nanostructured layers composed of porous silicon (PSi)-based silver (Ag) nanodendrites have been formed by a simple single-step electrochemical anodic oxidation process on p-type silicon substrate....

Resistive Switching Behaviour of Dip Coated ZnO Films with the Changing with Drawal Speed

Zinc Oxide (ZnO) thin films were produced by the sol gel dip coating process on the p-type silicon substrate with various withdrawal speeds changing from 1 to 4 cm/min, respectively. The films were annealed at a temperature of 500 °C for an hour in air ambient. The thin film thickness was found to be raised with the rise in withdrawal speed. The uniform distribution of the grains was appeared for all the films. The evolution of c-axis oriented (002) peak was revealed from X-ray diffraction (XRD) studies. The microstructural and optical properties of ZnO films were investigated by Raman, FTIR and photoluminescence spectroscopy (PL). The resistive switching properties of ZnO based memristors were studied by performing the current-voltage (I-V) measurements, where the thin films coated with lower withdrawal speed, have shown better switching property with rapid rise and fall of current during SET and RESET process, respectively.

Probing bias and power dependency of high-performance broadband Mg/ZnSnP2/Sn back-to-back Schottky junction photodetectors

Two non-identical Mg/ZnSnP2 and ZnSnP2/Sn Schottky diodes connected in coplanar back-to-back configuration are fabricated on p-type silicon (100) substrate for photodetection in the UV-VIS-NIR spectral region. A detailed study of the power and bias dependent responsivity, detectivity, and response and recovery speed of the devices is reported. The responsivity and detectivity were found to be 0.2 A W-1 and 4.62 × 1012 Jones for the Mg/ZnSnP2 and 0.03 A W-1 and 1.62 × 1011 Jones for the Sn/ZnSnP2 junctions, respectively when they were operated without bias. However, under a reverse bias of 2.5 V, these values changed to 4.7 A W-1 and 1.19 × 1012 Jones in the case of Mg/ZnSnP2 and 12.7 A W-1 and 4.78 × 1011 Jones for Sn/ZnSnP2 junctions, respectively. The photocurrents associated with both the junctions were increased superlinearly with illumination power which is correlated to the conversion of the existing traps within the forbidden energy gap to the recombination centers. The response and recovery speed of the photodetectors were also studied under variable bias and illumination power. Under an incident power of 0.34 mW, the rise and decay times for the Mg/ZnSnP2 and Sn/ZnSnP2 junctions were 200 μs, 2300 μs and 390 μs, 240 μs, respectively at 2.5 V. The Mg/ZnSnP2 showed an anomalous bias dependent secondary decay channel which disappeared at self-powered configuration. The frequency-dependent capacitance in the dark and illumination power-dependent capacitance of the structure were also performed to understand the presence of defect states and the capture of photogenerated carriers by the traps and recombination centers.

A Deep Level Transient Spectroscopy Study of Hole Traps in GexSe1−x-based Layers for Ovonic Threshold Switching Selectors

The deep levels in amorphous Ge0.5Se0.5 layers have been analyzed by Deep Level Transient Spectroscopy (DLTS). To that end, Metal-Insulator-Semiconductor (MIS) capacitors have been prepared by Physical Vapor Deposition of the films on p-type silicon substrates. A so-called quasi-constant capacitance procedure has been developed to account for the strong flat-band voltage shift of the capacitance-voltage characteristic with temperature. Applying this procedure to the as-deposited layers in the subthreshold regime reveals a dominant broad hole trap, with deep level parameters (trap concentration, hole capture cross section and activation energy) that strongly depend on the deposition conditions and the layer thickness. It is, finally, shown that the trap filling behavior does not follow the capture kinetics for simple point defects. Based on this observation, arguments are presented for an alternative analysis of the DLTS data.

120 MeV Ag ion irradiation induced intermixing, grain fragmentation in HfO2/GaOx thin films and consequent effects on the electrical properties of HfO2/GaOx/Si-based MOS capacitors

On p-type Silicon (100) substrates GaOx (150 nm) and HfO2 (30 nm) thin films have been synthesized using the RF magnetron sputtering method. After 120 MeV Ag SHI irradiation, ion-induced inter-diffusion/inter-mixing of Hf and Ga elements has been observed which leads to the development of inter-mixing of layers at the interfaces. As deposited films have randomly oriented large, inhomogeneous and non-uniform grains with an average size of 34.5 nm, while at the highest fluence, the formation of homogeneous and uniform individual spherical grains with an average size of 13.8 nm has been observed. Furthermore, HfO2/GaOx/Si-based MOS capacitors have been fabricated and the consequent effects on the electrical properties of these devices have been discussed in detail.

Development and characterization of ZnO thin film for piezoelectric applications

This paper reports a structural study of the ZnO thin film deposited on p-type silicon substrate using radio frequency (RF) sputtering technique. The structural study of the deposited ZnO thin film is done. The X-ray diffraction (XRD) spectra shows a strong peak of (0 0 2) orientation which ensures high quality of piezoelectric film. The roughness of the ZnO film is measured and found to be 1.85 nm which attributed to lower acoustic loss during wave propagation. These sputtering parameters can be used to deposit good quality ZnO thin film which can be utilized as piezoelectric layer in acoustic sensors, pressure sensors and many other optoelectronics devices.

SIMULATION AND FABRICATION OF Ag/ZnO-NANORODS/Ag ULTRAVIOLET DETECTORS ON p-TYPE SILICON

Hydrothermal method was successfully utilized to grow ZnO-nanorods on p-type silicon substrate. The highly dense grown ZnO-nanorods are well-aligned, and perpendicularly to substrate confirmed by scanning electron microscopy. The X-ray diffraction analysis confirmed that the [002] orientation was the major growth direction of the ZnO nanorods. A shadow masks have used to fabricate Metal–semiconductor–metal (MSM) structure. Three arrays of Ag interdigitated electrodes were then deposited onto the ZnO-nanorod/Si substrates. The current characteristics of [Ag/ZnO-nanorod/Ag]/Si devices were investigated range of -2 to +2 V. The as-fabricated devices showed a contrast ratio (i.e., the photocurrent/dark current) of 1.17 along with room temperature 0.115 mA/W responsivity at 365 nm and -2 V. A simulation analysis for the theoretical MSM structure has also been done in this work. A Visual TCAD was also used to simulate this device. A comparative study of experimentally and theoretically obtained results was also carried out and both results were found in good agreement of each other.

Microwave Power Detection With Voltage-Gated Graphene

Commercially available, chemical vapor deposition grown, graphene has been used to realize voltage-gate tunable, microwave power detectors. Corbino disc structures with chrome/gold contacts have been fabricated on top of graphene deposited on P-type silicon substrates with silicon dioxide gate oxides. Devices of varying sizes were used to detect a 433.92 MHz signal. These test structures exhibited a peak power detection sensitivity of 3.25 mV/mW at 292 K and 5.43 mV/mW at 80 K. The improved graphene detectors exceed the sensitivity of previously reported graphene detectors, 0.86 mV/mW, as well as previously explored carbon nanotube bolometers, 0.36 mV/mW.

Морфология, структурные и оптические свойства наноструктур кремния, полученные в растворе, содержащем гексафторосиликат водорода H-=SUB=-2-=/SUB=-(SiF-=SUB=-6-=/SUB=-)

Boron doped porous silicon with the observed photoluminescence with a crystallographic orientation of (100), which was fabricated based on a p-type silicon substrate using electrochemical etching in a solution containing hexafluorosilicic acid and ethyl alcohol was studied. A comparative analysis of the morphology, structural and optical properties of silicon nanostructures obtained in a solution containing H2(SiF6) and ethanol and samples obtained in a solution containing HF and ethanol was performed. Morphology, structural and optical properties were studied using scanning probe microscopy and spectrophotometry. It was shown that samples of porous silicon obtained in a solution containing H2(SiF6) and ethanol are characterized by improved optical properties, in particular, they exhibit more intense photoluminescence compared to samples obtained in solutions with HF and ethyl alcohol.

On capacitance–voltage characteristics of non-hydrogenated amorphous silicon/crystalline silicon heterojunctions for solar-cell applications

This work presents the performance of a HIT (Heterojunction with Intrinsic Thin layer) solar cell which was fabricated for the first time in the Advanced Electronics Laboratory of Batna 2 University by sputtering silicon on p-type crystalline silicon substrate. This initial effort was a tentative to learn about the fabrication technique and the control of the deposition parameters involved in the fabrication process. Preliminary capacitance voltage measurements confirm an abrupt junction model in consistence with the earlier published data. A junction depth of 0.58 µm and a diffusion voltage of 1.65 V were obtained. A defect density in the gap of non-hydrogenated amorphous silicon of 6.93 1014 cm−3 was computed indicating the presence of defect states.

Влияние малых доз гамма-излучения на оптические свойства наноструктурированного кремния, полученного методом металл-стимулированного химического травления in situ

Влияние малых доз гамма-излучения на оптические свойства наноструктурированного кремния, полученного методом металл-стимулированного химического травления in situ

Structural and Optical Properties for Nanostructure (Ag2O/Si & Psi) Films for Photodetector Applications

Ag2O (Silver Oxide) is an important p-type (in chasm to most oxides which were n-type), with a high conductivity semiconductor. From the optical absorbance data, the energy gap value of the Ag2O thin films was 1.93 eV, where this value substantially depends on the production method, vacuum evaporation of silver, and optical properties of Ag2O thin films are also affected by the precipitation conditions. The n-type and p-type silicon substrates were used with porous silicon wafers to precipitate ±125 nm, as thick Ag2O thin film by thermal evaporation techniques in vacuum and via rapid thermal oxidation of 400oC and oxidation time 95 s, then characterized by measurement of XRD, optical properties and scanning electron microscopy properties (SEM). Maximum value of photo response obtained from p-Ag2O/p-PS/Si photodetector results revealed two peak sat 600 nm and 800 nm. According to the x-ray diffraction four peaks appear, (111), (200), (110) and (311) Ag, respectively, (polycrystalline film) and lattice constant of (4.077 Å). Also the results showed a sharp increasing in the absorption-wave length plot of Ag2O film at UV and IR regions. The accumulation of the stars-like are semi-regular of the Ag2O nanocrystals on the surface of p-type PS and the other diffuse inside the pores in a nearly uniform distribution with a different grain size on the surface. The results of the dislocation density and strain are decreased with the grain size increasing.

Effect of adding ZHS microcubes on ZnO nanorods for CO2 gas sensing applications

Conventionally, the catalytic promotion of semiconductor metal oxide-based CO2 sensors response is simply based on chemical reaction. In most realistic applications, the sensors are operated in both sensing gas and light surrounding. Hence, we try to use a new type of catalyst, such as ZnSn(OH)6 (ZHS) has both chemical and photo catalytic functions to improve gas response more significantly. In this work, ZnO nanorods are deposited on p-type silicon substrate with and without ZHS microcubes covered on the top. The effects of adding the ZHS microcubes on CO2 sensing response have been studied in detail with experimental measurements. Experimental results show that the added ZHS microcubes promote CO2 response up to 350%, which is higher than the reported CO2 sensors with or without metal catalyst.

Studies on microstructure, residual stress, electrical and magnetic properties of nano-crystalline Ni–Cu alloy films deposited by DC magnetron co-sputtering

Nanocrystalline Ni–Cu alloy films with varying Cu concentration from 11% to 43% have been deposited on p-type silicon (100) substrate by DC magnetron co-sputtering. X-ray diffraction technique (XRD) has been used for phase identification, grain size determination and residual stress measurement. Compressive nature of residual stress has been observed in NiCu alloy films. A field emission scanning electron microscopy (FESEM) and a transmission electron microscope (TEM) have been used for the both microstructural and compositional analyses. The electrical resistivity measured by Vander Pauw four probe method increases with increase in alloying element (Cu) concentration in the Ni–Cu alloy films. The magnetic properties analyzed by superconducting quantum interference device (SQUID) shows decrease in both coercivity and saturation magnetization with increase in Cu concentration.