Carrier Diffusivity in Highly Excited Bulk SiC, GaN, and Diamond Crystals by Optical Probes

2012 ◽  
Vol 717-720 ◽  
pp. 309-312 ◽  
Author(s):  
Kęstutis Jarašiūnas ◽  
Patrik Ščajev ◽  
Tadas Malinauskas ◽  
Masashi Kato ◽  
Evgenii Ivakin ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Carrier Density ◽  
Room Temperature ◽  
Wide Bandgap ◽  
Optical Monitoring ◽  
Excess Carrier ◽  
Carrier Scattering ◽  
Diamond Crystals ◽  
Bandgap Semiconductors ◽  
The Impact

Optical monitoring of diffusivity in wide bandgap semiconductors was performed by using a picosecond light-induced transient grating technique. The bandgap renormalization and carrier-carrier scattering manifested itself at room temperature as two-fold decrease of the ambipolar diffusion coefficient Da in cubic SiC and 5-fold decrease of Da in diamond at excess carrier density N > 1017cm-3, while for GaN the impact was observed only at T 19cm-3, the plasma degeneracy led to enhanced Davalues in SiC and GaN and compensated the diffusivity decrease in diamond.

Er-Implanted Porous Silicon: a Novel Material for Si-Based Infrared LEDs

1994 ◽  
Vol 358 ◽  
Author(s):  
Fereydoon Namavar ◽  
F. Lu ◽  
C.H. Perry ◽  
A. Cremins ◽  
N.M. Kalkhoran ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Room Temperature ◽  
Wide Bandgap ◽  
Device Fabrication ◽  
Porous Si ◽  
High Concentration ◽  
Light Emitting ◽  
Novel Material ◽  
Bandgap Semiconductors ◽  
Ir Emission

ABSTRACTWe have demonstrated a strong, room-temperature, 1.54 μm emission from erbium-implanted at 190 keV into red-emitting porous silicon. Luminescence data showed that the intensity of infrared (IR) emission from Er implanted porous Si annealed at ≤ 650°C, was a few orders of magnitude stronger than Er implanted quartz produced under identical conditions, and was almost comparable to IR emission from In0.53Ga0.47As material which is used for commercial IR light-emitting diodes (LEDs).The strong IR emission (much higher than Er in quartz) and the weak temperature dependency of Er in porous Si, which is similar to Er3+ in wide-bandgap semiconductors, suggests that Er is not in SiO2 or Si with bulk properties but, may be confined in Si light-emitting nanostructures. Porous Si is a good substrate for rare earth elements because: 1) a high concentration of optically active Er3+ can be obtained by implanting at about 200 keV, 2) porous Si and bulk Si are transparent to 1.54 μm emission therefore, device fabrication is simplified, and 3) although the external quantum efficiency of visible light from porous Si is compromised because of self-absorption, it can be used to pump Er3+.

(Invited) Room Temperature Wafer Bonding of Wide Bandgap Semiconductors

2018 ◽  
Vol 86 (5) ◽  
pp. 3-21
Author(s):  
Fengwen Mu ◽  
Yinghui Wang ◽  
Tadatomo Suga
Keyword(s):  
Wafer Bonding ◽  
Room Temperature ◽  
Wide Bandgap ◽  
Wide Bandgap Semiconductors ◽  
Bandgap Semiconductors

scholarly journals The Influence of Recrystallization on Zinc Oxide Microstructures Synthesized with Sol–Gel Method on Scintillating Properties

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 533
Author(s):  
Ewelina Nowak ◽  
Mirosław Szybowicz ◽  
Alicja Stachowiak ◽  
Daria Piechowiak ◽  
Andrzej Miklaszewski ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Sapphire Substrate ◽  
Room Temperature ◽  
Sol Gel ◽  
Wide Bandgap ◽  
Luminescence Analysis ◽  
Gel Method ◽  
Sol Gel Method ◽  
Different Temperatures ◽  
Bandgap Semiconductors

Zinc oxide (ZnO) is one of the wide-bandgap semiconductors, which may be useful in a plethora of electronic, optical, piezoelectric, and scintillating applications. The following article consists in a structural and luminescence analysis of ZnO microfilms grown on a sapphire substrate with a sol–gel method. The films were annealed at different temperatures. The structures were investigated with the XRD and Raman methods, by which the influence of the substrate on the structure of the film was determined. The luminescence of films was investigated with room-temperature fluorescence, radioluminescence, and thermoluminescence.

IMPACT IONIZATION AND HIGH FIELD EFFECTS IN WIDE BAND GAP SEMICONDUCTORS

2001 ◽  
Vol 11 (02) ◽  
pp. 511-524 ◽  
Author(s):  
M. REIGROTZKI ◽  
J. R. MADUREIRA ◽  
A. KULIGK ◽  
N. FITZER ◽  
R. REDMER ◽  
...  
Keyword(s):  
Electric Fields ◽  
High Field ◽  
Impact Ionization ◽  
Electron Distribution Function ◽  
Wide Band ◽  
Ionization Rate ◽  
Wide Bandgap ◽  
Bandgap Semiconductors ◽  
Impact Ionization Rate ◽  
The Impact

Impact ionization plays a crucial role for electron transport in wide-bandgap semiconductors at high electric fields. Therefore, a realistic band structure has to be used in calculations of the microscopic scattering rate, as well as high field quantum corrections such as the intercollisional field effect. Here we consider both, and evaluate the impact ionization rate for wide-bandgap materials such as ZnS. A pronounced softening of the impact ionization threshold is obtained, as found earlier for materials like Si and GaAs. This field dependent impact ionization rate is included within a full-band ensemble Monte Carlo simulation of high field transport in ZnS. Although the impact ionization rate itself is strongly affected, little effect is observed on measurable quantities such as the impact ionization coefficient or the electron distribution function itself.

UV p-i-n PHOTODIODES MADE ON WIDE BANDGAP SEMICONDUCTORS

2008 ◽  
Vol 22 (05) ◽  
pp. 369-381
Author(s):  
FERDINAND V. GASPARYAN
Keyword(s):  
Room Temperature ◽  
Function Versus ◽  
Wide Band ◽  
Negative Resistance ◽  
Wide Bandgap ◽  
Current Voltage Characteristic ◽  
Wide Band Gap ◽  
Current Voltage ◽  
Wide Band Gap Semiconductors ◽  
Bandgap Semiconductors

In this paper, results of investigations on the static and dynamic characteristics, responsivity, internal noises, detectivity and noise equivalent power of the forward biased p-i-n photodiode made on wide band gap semiconductors operating in double injection regime are presented. Numerical simulations were made for 4H-SiC and GaN . It is shown that forward biased p-i-n photodiodes have high values of responsivity (~ 0.03 A/W for 4H-SiC and ~ 0.15 A/W for GaN ), detectivity (~1011 cm Hz 1/2 W-1 for 4H-SiC and ~ 8×1013 cm Hz 1/2 W-1 for GaN ) and low level of internal noises at room temperature. It is shown also that dynamic negative resistance on the current–voltage characteristic can come into existence and that the reactive part of the impedance is the sign-changed function versus frequency.

scholarly journals Experimental study of the supercritical CO 2 diffusion coefficient in porous media under reservoir conditions

2019 ◽  
Vol 6 (6) ◽  
pp. 181902 ◽  
Author(s):  
Junchen Lv ◽  
Yuan Chi ◽  
Changzhong Zhao ◽  
Yi Zhang ◽  
Hailin Mu
Keyword(s):  
Porous Media ◽  
Diffusion Coefficient ◽  
Oil Recovery ◽  
Carbon Capture ◽  
Carbon Capture And Storage ◽  
Elevated Pressure ◽  
Experimental Results ◽  
Saturated Porous Media ◽  
Reservoir Conditions ◽  
The Impact

Reliable measurement of the CO 2 diffusion coefficient in consolidated oil-saturated porous media is critical for the design and performance of CO 2 -enhanced oil recovery (EOR) and carbon capture and storage (CCS) projects. A thorough experimental investigation of the supercritical CO 2 diffusion in n -decane-saturated Berea cores with permeabilities of 50 and 100 mD was conducted in this study at elevated pressure (10–25 MPa) and temperature (333.15–373.15 K), which simulated actual reservoir conditions. The supercritical CO 2 diffusion coefficients in the Berea cores were calculated by a model appropriate for diffusion in porous media based on Fick's Law. The results show that the supercritical CO 2 diffusion coefficient increases as the pressure, temperature and permeability increase. The supercritical CO 2 diffusion coefficient first increases slowly at 10 MPa and then grows significantly with increasing pressure. The impact of the pressure decreases at elevated temperature. The effect of permeability remains steady despite the temperature change during the experiments. The effect of gas state and porous media on the supercritical CO 2 diffusion coefficient was further discussed by comparing the results of this study with previous study. Based on the experimental results, an empirical correlation for supercritical CO 2 diffusion coefficient in n -decane-saturated porous media was developed. The experimental results contribute to the study of supercritical CO 2 diffusion in compact porous media.

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