Deep Level Energy Analysis of Surface and Bulk Defects Using a Noncontact Laser/Microwave Photoconductance Technique

1992 ◽  
Vol 261 ◽  
Author(s):  
A. Buczkowski ◽  
G. A. Rozgonyi ◽  
F. Shimura
Keyword(s):  
Energy Analysis ◽  
Deep Level ◽  
Energy Levels ◽  
Surface Recombination ◽  
Surface Recombination Velocity ◽  
Level Energy ◽  
Recombination Lifetime ◽  
Recombination Processes ◽  
Bulk Energy ◽  
Recombination Velocity

ABSTRACTA noncontact technique for deep level energy analysis has been discussed based on a laser excitation/microwave reflection transient photoconductance procedure. An algorithm for separation of surface and bulk recombination effects was developed to independently determinesurface and bulk energy states. Deep energy levels associated with trapping and recombination processes have been calculated from the temperature dependence of surface recombination velocity and bulk recombination lifetime, based on state occupation statistics. Results have been compared with conventional DLTS data for silicon samples intentionally doped with metals during crystal growth.

scholarly journals The surface recombination velocity and bulk lifetime influences on photogenerated excess carrier density and temperature distributions in n-type silicon

2018 ◽  
Vol 31 (2) ◽  
pp. 313-328 ◽  
Author(s):  
Dragana Markushev ◽  
Dragan Markushev ◽  
Slobodanka Galovic ◽  
Sanja Aleksic ◽  
Dragan Pantic ◽  
...  
Keyword(s):  
Carrier Density ◽  
Surface Recombination ◽  
Surface Recombination Velocity ◽  
Excess Carrier ◽  
Experimental Scheme ◽  
Type Silicon ◽  
Temperature Distributions ◽  
Recombination Processes ◽  
Sensitive Function ◽  
Recombination Velocity

The temperature distributions in the n-type silicon circular plate, excited by a frequency-modulated light source from one side, are investigated theoretically in the frequency domain. The influence of the photogenerated excess carrier density on the temperature distributions is considered with respect to the sample thickness, surface quality and carrier lifetime. The presence of the thermalization and non-radiative recombination processes are taken into account. The existence of the fast and slow heat sources in the sample is recognized. It is shown that the temperature distribution on sample surfaces is a sensitive function of an excess carrier density under a bulk and surface recombination. The most favorable values of surface velocities ratio and bulk lifetime are established, assigned for a simpler and more effective analysis of the carrier influence in semiconductors. The photothermal and photoacoustic transmission detection configuration is proposed as a most suitable experimental scheme for the investigation of the excess carrier influence on the silicon surface temperatures.

Deep Traps and Charge Carrier Lifetimes in 4H-SiC Epilayers

2006 ◽  
Vol 527-529 ◽  
pp. 493-496 ◽  
Author(s):  
Sung Wook Huh ◽  
Joseph J. Sumakeris ◽  
A.Y. Polyakov ◽  
Marek Skowronski ◽  
Paul B. Klein ◽  
...  
Keyword(s):  
Deep Level ◽  
Surface Recombination ◽  
Deep Trap ◽  
Analytical Form ◽  
Optical Injection ◽  
Surface Recombination Velocity ◽  
Time Resolved ◽  
Electron Traps ◽  
Carrier Lifetimes ◽  
Recombination Velocity

Carrier lifetimes and the dominant electron and hole traps were investigated in a set of thick (9-104mm) undoped 4H-SiC epitaxial layers grown by CVD homoepitaxy. Deep trap spectra were measured by deep level transient spectroscopy (DLTS) with electrical or optical injection, while lifetimes were measured by room temperature time-resolved photoluminescence (PL). The main electron traps detected in all samples were due to Ti, Z1/Z2 centers, and EH6/EH7 centers. Two boron-related hole traps were observed with activation energies of 0.3 eV (boron acceptors) and 0.6 eV (boron-related D centers). The concentration of electron traps decreased with increasing layer thickness and increased toward the edge of the wafers. PL lifetimes were in the 400 ns-1800 ns range with varying injection and generally correlated with changes in the density of Z1/Z2 and to a lesser extent the EH6/EH7 electron traps. However, the results of DLTS measurements on p-i-n diode structures suggest that the capture of injected holes is much more efficient for the Z1/Z2 traps compared to the EH6/EH7 centers making the Z1/Z2 more probable candidates for the role of lifetime killers. A good fit of the thickness dependence of the measured lifetimes to the usual analytical form was obtained assuming that Z1/Z2 is the dominant hole recombination center and that the surface recombination velocity was 2500 cm/sec.

Cathodoluminescence of semiconductors at 200 eV?

1991 ◽  
Vol 49 ◽  
pp. 840-841
Author(s):  
S. Myhajlenko
Keyword(s):  
Room Temperature ◽  
Laser Annealing ◽  
Deep Level ◽  
Surface Recombination ◽  
Surface Recombination Velocity ◽  
Near Surface ◽  
Luminescence Efficiency ◽  
Experimental Configuration ◽  
Recombination Velocity

Brillson and Vitturo have recently reviewed the application of low energy (300 - 3000 eV) cathodoluminescence (CL) to surface studies of various semiconductors. In principle, the resulting electron penetration (40 - 1500 Å) at these energies should make it possible to differentiate near surface from bulk phenomena. The above authors demonstrated that deep level spectral features could be correlated with changes in the electronic structure of the surface as a result of metallization, laser annealing and thermal desorption. However, the experimental configuration used in the above studies was a room temperature, UHV-based, glancing incidence electron beam apparatus, i.e., no imaging capabilities. A future development in this area would be measurements performed in a regular SEM at cryogenic temperatures. The luminescence efficiency of GaAs greatly increases at low temperatures, and therefore, this would be beneficial to CL signal detection. We also require a better understanding of the factors which may limit progress in this matter. For example, the role of surface recombination velocity, the properties of luminescence dead layers and cross-over voltage phenomena are important to such an investigation. We report on progress in addressing some of these questions.

scholarly journals Annealing Effect on Photoacoustic Characterization of NiSe Metal Chalcogenide Semiconductor Using Phase Signal Analysis

2015 ◽  
Vol 1107 ◽  
pp. 526-529
Author(s):  
Pik Yee Chin ◽  
Zainal Abidin Talib ◽  
Wan Mahmood Mat Yunus ◽  
Josephine Liew Ying Chyi ◽  
Nordin Sabli ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Thermal Diffusivity ◽  
Annealing Temperature ◽  
Surface Recombination ◽  
Annealing Effect ◽  
Surface Recombination Velocity ◽  
Carrier Diffusion ◽  
Recombination Lifetime ◽  
Phase Signal ◽  
Recombination Velocity

Nickel selenide (NiSe) has been synthesized by solid state method and annealed at five different temperatures, ranging from 323 K to 823 K. The annealing effect on NiSe thermal and carrier transport properties were investigated by using open-cell photoacoustic technique. From analysis of its phase signal-frequency, thermal diffusivity, carrier diffusion coefficient, surface recombination velocity and recombination lifetime of the NiSe was determined. The results show that with increasing of the annealing temperature of NiSe sample, the thermal diffusivity and the carrier diffusion coefficient increased. The surface recombination velocity was decreasing as the annealing temperature of the sample increased. The increasing of annealing temperature of the sample also affected the trend of band-to-band recombination lifetime.

scholarly journals Numerical Simulation Analysis of Ag Crystallite Effects on Interface of Front Metal and Silicon in the PERC Solar Cell

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 592
Author(s):  
Myeong Sang Jeong ◽  
Yonghwan Lee ◽  
Ka-Hyun Kim ◽  
Sungjin Choi ◽  
Min Gu Kang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
High Efficiency ◽  
Open Circuit Voltage ◽  
Surface Recombination ◽  
Open Circuit ◽  
Surface Recombination Velocity ◽  
Metal Interface ◽  
Ag Crystallites ◽  
Recombination Velocity

In the fabrication of crystalline silicon solar cells, the contact properties between the front metal electrode and silicon are one of the most important parameters for achieving high-efficiency, as it is an integral element in the formation of solar cell electrodes. This entails an increase in the surface recombination velocity and a drop in the open-circuit voltage of the solar cell; hence, controlling the recombination velocity at the metal-silicon interface becomes a critical factor in the process. In this study, the distribution of Ag crystallites formed on the silicon-metal interface, the surface recombination velocity in the silicon-metal interface and the resulting changes in the performance of the Passivated Emitter and Rear Contact (PERC) solar cells were analyzed by controlling the firing temperature. The Ag crystallite distribution gradually increased corresponding to a firing temperature increase from 850 ∘C to 950 ∘C. The surface recombination velocity at the silicon-metal interface increased from 353 to 599 cm/s and the open-circuit voltage of the PERC solar cell decreased from 659.7 to 647 mV. Technology Computer-Aided Design (TCAD) simulation was used for detailed analysis on the effect of the surface recombination velocity at the silicon-metal interface on the PERC solar cell performance. Simulations showed that the increase in the distribution of Ag crystallites and surface recombination velocity at the silicon-metal interface played an important role in the decrease of open-circuit voltage of the PERC solar cell at temperatures of 850–900 ∘C, whereas the damage caused by the emitter over fire was determined as the main cause of the voltage drop at 950 ∘C. These results are expected to serve as a steppingstone for further research on improvement in the silicon-metal interface properties of silicon-based solar cells and investigation on high-efficiency solar cells.

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