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Electrical properties of nanostructure n-ZnSe/p-Si(100) heterojunction thin film diode
(2018-01-01)
Wongcharoen, Ngamnit
;
Gaewdang, Thitinai
The ZnSe/Si heterojunction is of specific interest since this structure provides effective solar cell and enables the integration of wide bandgap device in silicon circuits. It is known that the quality of the diode and the current transport mechanisms across the heterojunction may be greatly influenced by the quality of the interface and depends on the crystallinity of the film layer. In this work, n-ZnSe/p-Si(100) heterojunction was fabricated by thermal evaporating ZnSe thin films on p-Si (100) substrates. The current-voltage characteristics of n-ZnSe/p-Si(100) heterojunction were investigated in temperature range 20-300 K. Some important parameters such as barrier height, ideality factor and series resistance values evaluated by using thermionic emission (TE) theory and Cheung's method at room temperature are n = 2.910, øB<inf>0</inf> = 0.832 eV and 8.59×103 Ω, respectively. The temperature dependence of the saturation current and ideality factor are well described by tunneling enhanced recombination at junction interface with activation energy and characteristic energy values about 1.293 eV and E<inf>00</inf> = 95 meV, respectively. The carrier concentration of ZnSe thin films about 3.16×1013 cm-3 was deduced from the C-V measurements at room temperature. Admittance spectroscopy was employed for analysis of the defect energy levels situated in depletion region. The results showed that there was a single trap level whose position in the band gap was close to 0.04 eV above valence band. The results of this work may be useful for application such as heterojunction solar cells.
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Effect of rta on electrical characteristics of pt-doped p-n junction diode
(2017-02-01)
Chaiyasoonthorn, Sawatsakorn
;
Srithanachai, Itsara
;
Sangwaranatee, Narong
This paper investigates the effect of rapid thermal annealing (RTA) between 850 and 900°C. Platinum (Pt) atom will drive-into silicon structure by using RTA process and the influence of temperature. Therefore, we study the effects of temperature in RTA process to I-V characteristics of device are 850 and 900°C at 15 mins. After annealing process, the built-in voltage (Vbi ) is around 0.3-0.4eV, which means that Pt does not affect the device junction. The I-V characteristics after annealing show that at 900°C there is the worst leakage of current with slightly better than the forward current. In case of leakage current, it may occur from the Pt atom damage creation or trapping center in silicon structure.
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Power device impact using pt-doped on i-v characteristics
(2016-06-01)
Sangwaranatee, Narong
;
Srithanachai, Itsara
;
Yupapin, Preecha P.
We investigate the influence of Pt-doped in the power device, where the power device has been fabricated by using CMOS technology. Pt has high diffusion coefficient in the semiconductor material and Pt atom that can be used to reduce the device switching time. On the other hand, it may induce defects in device mechanism. The results obtained show that the Pt can penetrate into the silicon structure of 3,700A (before RTA process) by using the ion implantation 120keV. The Pt-doped device has shown the higher forward current of order 1. The goal of this experiment is to investigate the effect of Pt-doping on electrical characteristics of the power device.
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Temperature dependent current-voltage characteristics of n-type nanocrystalline-FeSi2/p-type Si heterojunctions fabricated by pulsed laser deposition
(2014-01-08)
Promros, Nathaporn
;
Iwasaki, Ryuhei
;
Funasaki, Suguru
;
Yamashita, Kyohei
;
Li, Chen
n-Type NC-FeSi<inf>2</inf>/p-type Si heterojunctions were successfully fabricated by PLD, and their forward current-voltage characteristics were analyzed on the basis of thermionic emission theory (TE) in the temperature range from 300 down to 77 K. With a decrease in the temperature, the ideality factor was increased while the zero-bias barrier height was decreased. The calculated values of ideality factor and barrier height were 3.07 and 0.63 eV at 300 K and 10.75 and 0.23 eV at 77 K. The large value of ideality factor indicated that a tunneling process contributes to the carrier transport mechanisms in the NC-FeSi<inf>2</inf> films. The series resistance, which was estimated by Cheung's method, was strongly dependent on temperature. At 300 K, the value of series resistance was 12.44 Ω and it was dramatically enhanced to be 1.71× 105 Ω at 77 K. © (2014) Trans Tech Publications, Switzerland.
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Electrical characteristics of n-type nanocrystalline FeSi2/intrinsic Si/ p-type Si heterojunctions prepared by facing-targets direct-current sputtering
(2014-01-01)
Promros, Nathaporn
;
Funasaki, Suguru
;
Iwasaki, Ryuhei
;
Yoshitake, Tsuyoshi
n-Type nanocrystalline FeSi<inf>2</inf>/intrinsic Si/p-type Si heterojunctions were prepared by FTDCS. In order to estimate their diode parameters such as ideality factor, barrier height and series resistance, their current-voltage characteristics were measured in the temperature range from 300 to 77 K and analyzed on the basis of thermionic emission theory and Cheung's method. Based on thermionic emission theory, the ideality factor was calculated from the slope of the linear part from the forward lnJ-V characteristics. The barrier height was calculated once the saturation current density was derived from the straight line intercept of lnJ-V plot at a zero voltage. The obtained results exhibit an increase of ideality factor and a decrease of barrier height at low temperatures, which might be owing to inhomogeneity of material and non-uniformity of charge at the interface. Based on Cheung's method, the ideality factor and barrier height were estimated from y-axis intercept of dV/d(lnJ)-J plot and y-axis intercept of H(J)-J plot, respectively. The series resistance was analyzed from the slopes of dV/d(lnJ)-J and H(J)-J plots. The values of ideality factor and barrier height obtained from this method are in agreement with those obtained from the thermionic emission theory. The obtained series resistances from dV/d(lnJ)-J and H(J)-J plots, which were approximately equal to each others, were increased as the temperature decreased. This result should be owing to the increased ideality factor and remarkably reduced carrier concentrations at low temperatures. © (2014) Trans Tech Publications, Switzerland.
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Current transport mechanism of n-type nanocrystalline FeSi2/intrinsic si/p-type si heterojunctions fabricated by facing-targets direct-current sputtering
(2013-10-29)
Promros, Nathaporn
;
Funasaki, Suguru
;
Iwasaki, Ryuhei
;
Yoshitake, Tsuyoshi
N-Type nanocrystalline FeSi<inf>2</inf>/intrinsic Si/p-type Si heterojunctions were successfully fabricated by FTDCS and their forward current-voltage characteristics at low temperatures were analyzed on the basis of thermionic emission theory. The analysis of J-V characteristics exhibits an increase in the ideality factor and a decrease in the barrier height at low temperatures. The values of ideality factor were estimated to be 2.26 at 300 K and 9.29 at 77 K. The temperature dependent ideality factor together with the constant value of parameter A indicated that a trap assisted multistep tunneling process is the dominant carrier transport mechanism in this heterojunction. At high voltages, the current transport mechanism is dominated by SCLC process. © (2013) Trans Tech Publications, Switzerland.
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Temperature dependence of electrical characteristics on pn junction power diodes irradiated by X-ray
(2012-10-02)
Sundarasaradula, Yuwadee
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Sodhgam, Piyachat
;
Amporn
;
Poyai
;
Klunngien, Nipapan
The purpose of this work is to study the effect of X-ray irradiation on pn junction power diode. The diodes were designed and fabricated using standard CMOS technology. Irradiation with exposure energy of 70 keV and various exposure times (5, 55, and 205 seconds) were applied on the diodes. The temperature dependence of the current-voltage (I-V) characteristics of the diodes was measured in the temperature range of 303K-393K. The effect on forward and reverse current can be explained through the following parameters such as saturation current (I <inf>o</inf>), series resistance (R <inf>s</inf>), and ideality factor (n). After irradiation the forward current was approximately three orders of magnitude higher than non-X-ray samples of all temperature conditions. This caused by the decreasing of the total series resistance. The increase in the values of I <inf>o</inf> with increasing temperature was observed. The value of n is essentially the same, close to 1, before X-ray and after X-ray of all temperature range of 303K-393K. © 2012 IEEE.

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