Carrier Scattering Mechanisms: Identification via the Scaling Properties of the Boltzmann Transport Equation

Abstract

A method based on the scaling properties of the Boltzmann transport equation is proposed to identify the dominant scattering mechanisms that affect charge transport in a semiconductor. This method uses drift velocity data of mobile charges at different lattice temperatures and applied electric fields and takes into account the effect of carrier heating. By performing time-of-flight measurements on single-crystalline diamond, hole and electron drift velocities are measured under low-injection conditions within the temperature range 10-300 K. Evaluation of the data using the proposed method identifies acoustic phonon scattering as the dominant scattering mechanism across the measured temperature range. The exception is electrons at 100-200 K where conduction-band valley repopulation has a prominent effect. At temperatures below ≈80 K, where valley polarization is observed for electrons, transport dominated by acoustic phonon scattering is observed in different valleys separately. The scaling model is additionally tested on data from highly resistive gallium arsenide samples to demonstrate the versatility of the method. In this case, impurity scattering can be ruled out as the dominant scattering mechanism in the samples for the temperature range 80-120 K.

Schottky Diode with Asymmetric Metal Contacts on WS2

“…Conversely, with In contacts and In-Au contacts, the electron mobility increases with decreasing temperature, exhibiting a significant suppression of phonon scattering on electrons, and leading to improved carrier mobility. [29,30] According to the thermionic emission theory, the current in the device can be obtained as follows…”

General strategies to improve thermoelectric performance with an emphasis on tin and germanium chalcogenides as thermoelectric materials

“…The (+) sign is for the VB, while the (−) sign is for the CB, D = dimensionality of the material, q = charge of the carrier, k B = Boltzmann constant, η = reduced Fermi energy = r = scattering parameter (+3/2-for ionized impurity scattering, −1/2-for acoustic phonon scattering, 0-for neutral impurity scattering). 34–36 If we take 3D-bulk material then, D = 3 and eqn (5) takes the form,…”

“…So the value of S is higher when ionized impurity scattering ( β = +3/2) dominates over neutral impurity ( β = 0) and acoustic phonon scattering ( β = −3/2-for DP scattering, and β = −1/2-for piezoelectric scattering). 35,36,45…”

“…So the value of S is higher when ionized impurity scattering (b ¼ +3/2) dominates over neutral impurity (b ¼ 0) and acoustic phonon scattering (b ¼ À3/2-for DP scattering, and b ¼ À1/2-for piezoelectric scattering). 35,36,45 So, the Seebeck coefficient can be modied by manipulating s-and changing the dominance of different scattering processes. A method of manipulation of s-is through resonant scattering by impurity and defect centers.…”

Latest directions in p-type transparent conductor design

“…However, there is a precarious balancing act to maintain, as adding too many charge carriers (by introducing defects into the system) can reduce their overall mobility due to scattering processes such as ionised impurity scattering, carriercarrier scattering, grain boundary scattering and both polar and non-polar electron-phonon scattering. [20][21][22] Charge carrier concentration is also intimately linked to transparency via the plasmon frequency o p 2 relationship, describing the oscillation of charge carriers within an applied field:…”