A Led Based on Porous Polycrystalline Silicon

1997 ◽  
Vol 486 ◽  
Author(s):  
W. N. Huang ◽  
K. Y. Tong ◽  
P. W. Chan
Keyword(s):  
Silicon Substrate ◽  
Polycrystalline Silicon ◽  
Polycrystalline Material ◽  
Forward Bias ◽  
Depletion Region ◽  
Silicon Substrates ◽  
Large Area ◽  
Electron Hole ◽  
Bright Spots ◽  
Current Characteristics

AbstractPrevious studies on electroluminescence in porous silicon were based on crystalline wafers. In this paper, we shall report the characteristics of a LED based on porous effects in a cast polycrystalline silicon substrate. A layer of porous region was first formed on a cast polycrystalline silicon substrate by anodization, followed by the deposition of a semitransparent Au layer. Under forward bias, the LED emits stable yellowish white light (with the presence of bright spots) for currents above 20 mA/cm2. From the electroluminescence spectra measured, we suggest that the emission is due to the recombination of electron-hole pairs in a microplasma region. We propose a model where the microplasma is present in the depletion region of the heterojunction formed between the bulk polysilicon and the surface porous polysilicon. The defects and grain boundaries in a polycrystalline material facilitate the formation of such microplasma. The heterojunction model will also be used to explain the current characteristics of the LED. The effect on the LED characteristics due to indium coating on the porous substrate prior to Au deposition was studied, and the results agree with the heterojunction model. Our work shows that cast polycrystalline silicon substrates have potential for LED fabrication in cheap and large area applications.

Preparation of Anodic Aluminum Oxide Nano-Templates on Polycrystalline Silicon Substrates

2013 ◽  
Vol 724-725 ◽  
pp. 63-66
Author(s):  
Guo Feng Ma ◽  
Hong Ling Zhang ◽  
Hong Bo Fu ◽  
Li Na Sun ◽  
Chun Lin He
Keyword(s):  
Aluminum Oxide ◽  
Silicon Substrate ◽  
Polycrystalline Silicon ◽  
Anodic Aluminum Oxide ◽  
Pure Aluminum ◽  
Oxalic Acid Solution ◽  
Average Diameter ◽  
Silicon Substrates ◽  
Anodic Aluminum ◽  
One Step

The anodic aluminum oxide (AAO) templates on polycrystalline silicon substrate are studied for growth of ordered nano-dot arrays in order to fabricate the porous silicon layers. The AAO templates on polycrystalline silicon substrate with pores of average diameter 50nm were successfully prepared by one-step anodization of high pure aluminum layer deposited on polycrystalline silicon in oxalic acid solution. Scanning electron microscopy (SEM) showed that alumina nano-pore arrays were nicely constructed with smooth wall morphologies and well-defined diameters.

Excitation Mechanisms and Light Emitting Device Performances in Er-Doped Crystalline Si

1996 ◽  
Vol 422 ◽  
Author(s):  
F. Priolo ◽  
S. Coffa ◽  
G. Franzo ◽  
A. Polman
Keyword(s):  
Reverse Bias ◽  
Crystalline Silicon ◽  
Forward Bias ◽  
Depletion Region ◽  
Impact Excitation ◽  
Electron Hole ◽  
Light Emitting ◽  
Temperature Operating ◽  
Excitation Mechanisms ◽  
Er Doped

AbstractIn this paper the performances of room temperature operating light emitting diodes (LEDs), fabricated by Er ion implantation of crystalline silicon, are investigated in detail. It is shown that 1.54 μm emission is observed under both forward and reverse bias operation, with a much higher intensity under reverse bias. The excitation mechanisms of Er3+ are demonstrated to be very different in the two cases: under forward bias Er is excited through the electron - hole recombination at an Er - related level, while under reverse bias impact excitation by hot carriers represents the excitation process. This last mechanism is shown to occur with a cross section of 6 × 10−17 cm2 and population inversion of the excitable Er sites within the depletion region is demonstrated. The efficiency and limitations of this approach are also discussed.

scholarly journals Binary Self-Assembly of Nanocolloidal Arrays using Concurrent and Sequential Spin Coating Techniques

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 274
Author(s):  
Shih-Jyun Shen ◽  
Demei Lee ◽  
Yu-Chen Wu ◽  
Shih-Jung Liu
Keyword(s):  
Silicon Substrate ◽  
Self Assembly ◽  
Spin Coating ◽  
Processing Parameters ◽  
The Self ◽  
Silicon Substrates ◽  
Processing Conditions ◽  
Polystyrene Spheres ◽  
Optimal Processing ◽  
Spin Coater

This paper reports the binary colloid assembly of nanospheres using spin coating techniques. Polystyrene spheres with sizes of 900 and 100 nm were assembled on top of silicon substrates utilizing a spin coater. Two different spin coating processes, namely concurrent and sequential coatings, were employed. For the concurrent spin coating, 900 and 100 nm colloidal nanospheres of latex were first mixed and then simultaneously spin coated onto the silicon substrate. On the other hand, the sequential coating process first created a monolayer of a 900 nm nanosphere array on the silicon substrate, followed by the spin coating of another layer of a 100 nm colloidal array on top of the 900 nm array. The influence of the processing parameters, including the type of surfactant, spin speed, and spin time, on the self-assembly of the binary colloidal array were explored. The empirical outcomes show that by employing the optimal processing conditions, binary colloidal arrays can be achieved by both the concurrent and sequential spin coating processes.

Fabrication and characteristics of the high-sensitivity humidity sensor of anodic aluminum oxide based on silicon substrates

2018 ◽  
Vol 32 (16) ◽  
pp. 1850199 ◽  
Author(s):  
Degao Lan ◽  
Xiaofeng Zhao ◽  
Fei Wang ◽  
Chunpeng Ai ◽  
Dianzhong Wen ◽  
...  
Keyword(s):  
Aluminum Oxide ◽  
Silicon Substrate ◽  
Anodic Aluminum Oxide ◽  
Nonlinear Response ◽  
Humidity Sensor ◽  
High Sensitivity ◽  
Silicon Substrates ◽  
High Porosity ◽  
Interdigitated Electrodes ◽  
Anodic Aluminum

The humidity sensor based on silicon substrate is presented in this paper, which consists of anodic aluminum oxide (AAO) film and interdigitated electrodes. By using electro-chemical oxidizing technique, AAO film with high porosity is fabricated on the silicon substrate. Under optimal oxidization condition, pore diameter of 37–79 nm and depth about [Formula: see text]m is achieved. Interdigitated electrodes are fabricated on the top of AAO film by vacuum evaporation deposition method. The results show that the sensor has different nonlinear response in whole range of relative humidity (RH). Moreover, it has almost linear relationship between the capacitance and RH at high RH from 75% to 95%. The highest sensitivity is obtained 613 pF/%RH at 1 kHz, which is much higher than other frequencies.

Influences of MOS Device Characteristic under Different Oxygen-Dose Participations in the Silicon Substrate

2015 ◽  
Vol 656-657 ◽  
pp. 8-13
Author(s):  
Shen Li Chen ◽  
Tsung Shiung Lee ◽  
Yu Ting Huang
Keyword(s):  
Silicon Substrate ◽  
Czochralski Method ◽  
Silicon Substrates ◽  
Trap Charge ◽  
Substrate Quality ◽  
Mos Devices ◽  
Starting Point ◽  
Charge Characteristic ◽  
Mos Device

A silicon substrate is the starting point of producing the semiconductor component, so that the quality of semiconductor substrate is very important during the VLSI fabrication. In this paper, we will evaluate the influence of MOS device characteristics under different oxygen impurities in silicon substrates. In the course of silicon substrate pulling process by Czochralski method, the defect and impurity will be existed; the oxygen atom will be induced substrate dislocations and affected the substrate quality. In this work, different oxygen doses will be used in wafer to study the impacts on MOS CV curve characteristic, interface trap charge characteristic, ID-VDScurve, ID-VGScurve, and threshold voltage behaviors of MOS devices.

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