• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.7
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• pp.69-76
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• 1995

A new device structure has been developed for p-i-n switches. In this structure, the phosphorus-diffused n$^{+}$ layter adjacent to the boron-doped anode is used to short the p$^{+}$ anode-channel(i-region). This change in the anode electrode structure results in a significant improvement in the threshold voltage-to-holding voltage($V_{Th}/V_{h}$) ratio, which is due to the suppression of the hold injection from the anode by the n$^{+}$ layer. The shorted anode p-i-n devices of a 100 .mu.m channel length show an extremely high threshold voltage in the 250~300 V range and a low holding voltage in the 5~9 V range. These features of the device are expected to acdelerate their practical application to power switching circuits.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.11
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• pp.974-979
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• 2009

We studied solution-processed single-layered phosphorescent organic light-emitting diodes (PHOLEDs), doped with ionic salt and treated with simultaneous electrical and thermal annealing. Because the simultaneous annealing causes the accumulation of salt ions at the electrode surfaces, the energy levels of the organic molecules are bent by the electric fields due to the adsorbed ions, i.e., the simultaneous annealing can induce the proper formation of an ionic p-i-n structure. As a result, an ionic p-i-n PHOLED with a peak luminescence of over ${\sim}35,000\;cd/m^2$ and efficiency of 27 cd/A was achieved through increased and balanced carrier-injections.

• Bulletin of the Korean Mathematical Society
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• v.34 no.4
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• pp.549-560
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• 1997

For positive integers $n_i \geq 2, i = 1, 2, 3, 4$, such that $\Sigma \frac{n_i}{1} < 2$, there exists a quadrilateral $P = P_1 P_2 P_3 P_4$ in the hyperbolic plane $H^2$ with the interior angle $\frac{n_i}{\pi}$ at $P_i$. Let $\Gamma \subset Isom(H^2)$ be the (discrete) group generated by reflections in each side of $P$. Then the quotient space $H^2/\gamma$ is a differentiable orbifold of type $(^* n_1 n_2 n_3 n_4)$. It will be shown that the deformation space of $Rp^2$-structures on this orbifold can be mapped continuously and bijectively onto the cell of dimension 4 - \left$\mid$ {i$\mid$n_i = 2} \right$\mid$$.

• Journal of Sensor Science and Technology
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• v.1 no.1
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• pp.5-12
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• 1992

We have fabricated a-Si:H multilayer for contact-type linear image sensor by means of RF glow discharge decomposition method. The ITO/i-a-Si:H/Al structure has relatively high dark current due to indium diffusion and carrier injection from both electrodes, resulting in low photocurrent to dark current. To suppress the dark current and to enhance interface electric field between ITO and i-a-Si:H film we have fabricated ITO/insulator/i-a-S:H/p-a-S:H/Al multilayer film with blocking structure. The photocurrent of ITO/$SiO_{2}(300{\AA})$/i-a-Si:H/p-a-Si:H($1500{\AA}$)/Al multilayer sensor with 5V bias voltage became saturated at about 20nA under $20{\mu}W/cm^{2}$ light intensity, while the dark current was less than 0.1nA. To increase the light generation efficiency we have adopted ITO/$SiO_{x}N_{y}(300{\AA})$/i-a-Si:H/p-a-Si:H($1500{\AA}$)/Al structure, showing photocurrent of 30nA and dark current of 0.08nA with 5V bias voltage. Also the spectral photosensitivity of the multilayer was enhanced for short wavelength visible region of 560nm, compared with that of the a-Si:H monolayer of 630nm. And its photoresponse time was about 0.3msec with the film homogeneity of 5% deviation.

• Transactions on Electrical and Electronic Materials
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• v.18 no.2
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• pp.70-73
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• 2017

We investigated n-i-p type single junction hydrogenated amorphous silicon oxide solar cells. These cells were without front surface texture or back reflector. Maximum power point efficiency of these cells showed that an optimized device structure is needed to get the best device output. This depends on the thickness and defect density ($N_d$) of the active layer. A typical 10% photovoltaic device conversion efficiency was obtained with a $N_d=8.86{\times}10^{15}cm^{-3}$ defect density and 630 nm active layer thickness. Our investigation suggests a correlation between defect density and active layer thickness to device efficiency. We found that amorphous silicon solar cell efficiency can be improved to well above 10%.

• Journal of Biomedical Engineering Research
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• v.18 no.3
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• pp.307-313
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• 1997

he photoconductive gain mechanism in amorphus silicon devices was investigated in connection with applications to radiation detection. Various device types such as p-i-n, n-i-n and i-i-p-i-n structures were fabricated and tested. Photoconductive gain was measured in two time scales : one for short pulses of visible light(<$1{\mu}sec$) which simulate the transit of energetic charged particles or ${\gamma}$-rays, and the other for rather long pulses of light(1msec) which simulate x-ray exposure in medical imaging, We used two definitions of phtoconductive gain : current gain and charge gain which is an integration of the current gain. We obtained typical charge gains of 3~9 for short pulses and a few hundreds for long pulses at a dark current density level of 10mA/$cm^2$. Various gain results are discussed in terms of the device structure, applied bias and dark current density.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.7
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• pp.56-61
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• 1997

I $n_{0.53}$G $a_{0.47}$As/I $n_{0.52}$A $l_{0.48}$As pseudomorphic high electron mobility transistor (P-HEMT) structures were grown on semi-insulating InP substrates by molecular beam epitzxy method. The hall effect measuremetn was used to measure the electrical properties and the photoluminescence (PL) measurement was used to measure the electrical properties and the photoluminescence(PL) measurement for optical propety. By the cross-sectional transmission electron microscopy (XTEM) investigation of the V and X shape defects including slip with angle of 60.deg. C and 120.deg. C to surface in the sampel, the defects formation mecahnism in the I $n_{0.52}$A $l_{0.48}$As epilayers on InP substrates could be explained with the different thermal expansion coefficients between I $n_{0.52}$A $l_{0.48}$As epilayers and InP substrate.d InP substrate.

• Journal of KIISE:Databases
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• v.29 no.1
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• pp.58-71
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• 2002

Generally, multi-dimensional data such as image and spatial data require large amount of storage space. There is a limit to store and manage those large amount of data in single workstation. If we manage the data on parallel computing environment which is being actively researched these days, we can get highly improved performance. In this paper, we propose a parallel high-dimensional index structure that exploits the parallelism of the parallel computing environment. The proposed index structure is nP(processor)-n$\times$mD(disk) architecture which is the hybrid type of nP-nD and lP-nD. Its node structure increases fan-out and reduces the height of a index tree. Also, A range search algorithm that maximizes I/O parallelism is devised, and it is applied to K-nearest neighbor queries. Through various experiments, it is shown that the proposed method outperforms other parallel index structures.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1469-1471
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• 1994

This paper describes the structure and electrical characteristics of a shorted anode p-i-n switch. The device showed a significant improvement in the threshold voltage-to-holding voltage ratio, which is due to the suppression of the hole injection from the anode and to the gold gettering at the anode side. The shorted anode devices with a $100{\mu}m$ channel length have a threshold voltage of 300 volts and a holding voltage of 5.5 volts.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.230-230
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• 2013

In amorphous or microcrystalline thin-film silicon solar cells, p-i-n structure is used instead of p/n junction structure as in wafer-based Si solar cells. Hence, these p-i-n structured solar cells inevitably consist of many interfaces and the cell efficiency critically depends on the effective control of these interfaces. In this study, in-situ plasma treatment process of the interfaces was developed to improve the efficiency of a-Si:H solar cell. The p-i-n cell was deposited using a single-chamber VHF-PECVD system, which was driven by a pulsed-RF generator at 80 MHz. In order to solve the cross-contamination problem of p-i layer, high RF power was applied without supplying SiH4 gas after p-layer deposition, which effectively cleaned B contamination inside chamber wall from p-layer deposition. In addition to the p-i interface control, various interface control techniques such as thin layer of TiO2 deposition to prevent H2 plasma reduction of FTO layer, multiple applications of thin i-layer deposition and H2 plasma treatment, H2 plasma treatment of i-layer prior to n-layer deposition, etc. were developed. In order to reduce the reflection at the air-glass interface, anti-reflective SiO2 coating was also adopted. The initial solar cell efficiency over 11% could be achieved for test cell area of 0.2 $cm^2$.