scholarly journals Minority carrier decay length extraction from scanning photocurrent profiles in two-dimensional carrier transport structures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yu-Chien Wei ◽  
Cheng-Hao Chu ◽  
Ming-Hua Mao
Keyword(s):  
Thin Film ◽  
Analytical Model ◽  
Carrier Transport ◽  
Minority Carrier ◽  
Diffusion Length ◽  
Schottky Contact ◽  
Decay Length ◽  
Two Dimensional ◽  
Decay Function ◽  
Simulation Results

AbstractCarrier transport was studied both numerically and experimentally using scanning photocurrent microscopy (SPCM) in two-dimensional (2D) transport structures, where the structure size in the third dimension is much smaller than the diffusion length and electrodes cover the whole terminal on both sides. Originally, one would expect that with increasing width in 2D transport structures, scanning photocurrent profiles will gradually deviate from those of the ideal one-dimensional (1D) transport structure. However, the scanning photocurrent simulation results surprisingly showed almost identical profiles from structures with different widths. In order to clarify this phenomenon, we observed the spatial distribution of carriers. The simulation results indicate that the integrated carrier distribution in the 2D transport structures with finite width can be well described by a simple-exponential-decay function with the carrier decay length as the fitting parameter, just like in the 1D transport structures. For ohmic-contact 2D transport structures, the feasibility of the fitting formula from our previous 1D analytical model was confirmed. On the other hand, the application of a simple-exponential-decay function in scanning photocurrent profiles for the diffusion length extraction in Schottky-contact 2D transport structures was also justified. Furthermore, our simulation results demonstrate that the scanning photocurrent profiles in the ohmic- or Schottky-contact three-dimensional (3D) transport structures with electrodes covering the whole terminal on both sides will reduce to those described by the corresponding 1D fitting formulae. Finally, experimental SPCM on a p-type InGaAs air-bridge two-terminal thin-film device was carried out. The measured photocurrent profiles can be well fitted by the specific fitting formula derived from our previous 1D analytical model and the extracted electron mobility-lifetime product of this thin-film device is 6.6 × 10–7 cm2·V−1. This study allows us to extract the minority carrier decay length and to obtain the mobility-lifetime product which can be used to evaluate the performance of 2D carrier transport devices.

scholarly journals Efficient Interlayer Exciton Transport in Two-Dimensional Metal-Halide Perovskites.

2020 ◽  
Author(s):  
Alvaro J Magdaleno ◽  
Michael Seitz ◽  
Michel Frising ◽  
Ana Herranz de la Cruz ◽  
Antonio I. Fernández-Domínguez ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Charge Carrier ◽  
Carrier Transport ◽  
Energy Transport ◽  
Diffusion Length ◽  
Charge Carrier Transport ◽  
Two Dimensional ◽  
Exciton Transport ◽  
Halide Perovskites ◽  
Excitonic Energy

We present transient microscopy measurements of interlayer energy transport in (PEA)<sub>2</sub>PbI<sub>4</sub> perovskite. We find efficient interlayer exciton transport (0.06 cm<sup>2</sup>/s), which translates into a diffusion length that exceeds 100 nm and a sub-ps timescale for energy transfer. While still slower than in-plane exciton transport (0.2 cm<sup>2</sup>/s), our results show that excitonic energy transport is considerably less anisotropic than charge-carrier transport for 2D perovskites.

Solution-processed two-dimensional layered heterostructure thin-film with optimized thermoelectric performance

2017 ◽  
Vol 19 (27) ◽  
pp. 17560-17567 ◽  
Author(s):  
Tongzhou Wang ◽  
Congcong Liu ◽  
Fengxing Jiang ◽  
Zhaofen Xu ◽  
Xiaodong Wang ◽  
...  
Keyword(s):  
Thin Film ◽  
Power Factor ◽  
Carrier Transport ◽  
Thermoelectric Performance ◽  
Two Dimensional ◽  
Transport Barrier ◽  
Solution Processed

The content of rGO could alter the carrier transport barrier, and the optimizing power factor was achieved at rGO–MS2 junctions.

Reentrant Growth in Kinetic Thin-Film Deposition on Stepped Surfaces

1995 ◽  
Vol 399 ◽  
Author(s):  
Rong-Fu Xiao
Keyword(s):  
Thin Film ◽  
Monte Carlo Simulation ◽  
Deposition Temperature ◽  
Diffusion Length ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Natural Phenomenon ◽  
Two Dimensional ◽  
Stepped Surfaces ◽  
Thin Film Epitaxy

ABSTRACTWe have studied the reentrant growth in kinetic thin-film deposition on stepped surfaces using a Monte Carlo simulation. The results show that the reentrant oscillation of two dimensional nucleation growth occurs as a result of the variation of surface diffusion length with deposition temperature, and that it is a natural phenomenon in kinetic thin-film epitaxy on a substrate with a permanent step source.

scholarly journals Efficient Interlayer Exciton Transport in Two-Dimensional Metal-Halide Perovskites.

2020 ◽  
Author(s):  
Alvaro J Magdaleno ◽  
Michael Seitz ◽  
Michel Frising ◽  
Ana Herranz de la Cruz ◽  
Antonio I. Fernández-Domínguez ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Charge Carrier ◽  
Carrier Transport ◽  
Energy Transport ◽  
Diffusion Length ◽  
Charge Carrier Transport ◽  
Two Dimensional ◽  
Exciton Transport ◽  
Halide Perovskites ◽  
Excitonic Energy

We present transient microscopy measurements of interlayer energy transport in (PEA)<sub>2</sub>PbI<sub>4</sub> perovskite. We find efficient interlayer exciton transport (0.06 cm<sup>2</sup>/s), which translates into a diffusion length that exceeds 100 nm and a sub-ps timescale for energy transfer. While still slower than in-plane exciton transport (0.2 cm<sup>2</sup>/s), our results show that excitonic energy transport is considerably less anisotropic than charge-carrier transport for 2D perovskites.

Correlation Between Minority Carrier Diffusion Length and Microstructure in a-Si:H Thin Films

1993 ◽  
Vol 297 ◽  
Author(s):  
G. Conte ◽  
G. Fameli ◽  
A. Rubino ◽  
E. Terzini ◽  
F. Villani ◽  
...  
Keyword(s):  
Steady State ◽  
Carrier Transport ◽  
Minority Carrier ◽  
Diffusion Length ◽  
Defect Density ◽  
Hydrogen Distribution ◽  
Steady State Condition ◽  
Hydrogenated Silicon ◽  
Morphological Variations ◽  
Amorphous Hydrogenated Silicon

Aim of this work is to investigate the opto-electronic properties of amorphous hydrogenated silicon (a-Si:H). The deposition temperature nas been used as a driving force to modify the morphology and bonded hydrogen distribution. The influence of the hydrogen microstructure on the carriers μτ product has been examined. The majority and minority carrier μτ have been evaluated from the diffusion length measurement, by using the Steady State Photocarrier Grating (SSPG) technique, and from the photoconductivity in the steady state condition (SSPC). The μτ values have been correlated with the defect density and the Fermi level position. Some considerations are proposed to explain the carrier transport in terms of the compositional inhomogeneities in Si:H alloys due to the morphological variations.

Surface recombination effects on minority carrier diffusion length measurements using electron beam-induced current

1990 ◽  
Vol 48 (4) ◽  
pp. 744-745
Author(s):  
D.P. Malta ◽  
M.L. Timmons
Keyword(s):  
Electron Beam ◽  
Beam Energy ◽  
Minority Carrier ◽  
Diffusion Length ◽  
Effective Diffusion ◽  
Surface Recombination ◽  
Surface Recombination Velocity ◽  
Logarithmic Scale ◽  
Minority Carrier Diffusion Length ◽  
Carrier Diffusion

Measurement of the minority carrier diffusion length (L) can be performed by measurement of the rate of decay of excess minority carriers with the distance (x) of an electron beam excitation source from a p-n junction or Schottky barrier junction perpendicular to the surface in an SEM. In an ideal case, the decay is exponential according to the equation, I = Ioexp(−x/L), where I is the current measured at x and Io is the maximum current measured at x=0. L can be obtained from the slope of the straight line when plotted on a semi-logarithmic scale. In reality, carriers recombine not only in the bulk but at the surface as well. The result is a non-exponential decay or a sublinear semi-logarithmic plot. The effective diffusion length (Leff) measured is shorter than the actual value. Some improvement in accuracy can be obtained by increasing the beam-energy, thereby increasing the penetration depth and reducing the percentage of carriers reaching the surface. For materials known to have a high surface recombination velocity s (cm/sec) such as GaAs and its alloys, increasing the beam energy is insufficient. Furthermore, one may find an upper limit on beam energy as the diameter of the signal generation volume approaches the device dimensions.

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