Magnetotransport in modulation-doped In0.53Ga0.47As/In0.52Al0.48As heterojunctions: in-plane effective mass, quantum and transport mobilities of 2D electrons

Superlattices and Microstructures

Çelik

Mutlu

et al. 2012

a b s t r a c tThe two-dimensional (2D) electron energy relaxation in Al 0.25 Ga 0.75 N/AlN/GaN heterostructures was investigated experimentally by using two experimental techniques; Shubnikov-de Haas (SdH) effect and classical Hall Effect. The electron temperature (T e ) of hot electrons was obtained from the lattice temperature (T L ) and the applied electric field dependencies of the amplitude of SdH oscillations and Hall mobility. The experimental results for the electron temperature dependence of power loss are also compared with the current theoretical models for power loss in 2D semiconductors. The power loss that was determined from the SdH measurements indicates that the energy relaxation of electrons is due to acoustic phonon emission via unscreened piezoelectric interaction. In addition, the power loss from the electrons obtained from Hall mobility for electron temperatures in the range T e > 100 K is associated with optical phonon emission. The temperature dependent energy relaxation time in Al 0.25 Ga 0.75 N/AlN/GaN heterostructures that was determined from the power loss data indicates that hot electrons relax spontaneously with MHz to THz emission with increasing temperatures.

“…It was found that the peak position shift with a factor of cos h and the oscillations disappear at h = 90°. This observation is a characteristic of 2D electron gas [19].…”

Section: à3mentioning

confidence: 54%

Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

“…3. The double-differentiation technique does not change the peak position or the period of the oscillations [19,23].…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 3 more Smart Citations

Temperature dependent energy relaxation time in AlGaN/AlN/GaN heterostructures

Superlattices and Microstructures

Çelik

Mutlu

et al. 2012

Determination of the In-Plane Effective Mass and Quantum Lifetime of 2D Electrons in Modulation-Doped In0.53Ga0.47As/In0.52Al0.48As Heterojunctions from the Quantum Oscillations in Hall Resistance

Cankurtaran

Çelik

et al. 2001

phys. stat. sol. (a)

Self Cite

Hall effect measurements as a function of magnetic field up to 2.3 T, performed in the temperature range between 3.3 and 12 K, have been used to investigate the electronic transport properties of modulation-doped In 0.53 Ga 0.47 As/In 0.52 Al 0.48 As heterojunctions with single-or double-subband occupancy. The carrier density (N i ) in each subband, the Fermi energy (E F --E i ) with respect to subband energy and subband separation (E 2 --E 1 ) have been determined from the periods of the quantum oscillations in Hall resistance. The in-plane effective mass (m * ) and the quantum lifetime (t q ) of 2D electrons in each subband have been obtained from the temperature and magnetic field dependences of the amplitude of the Hall oscillations, respectively. The results found for N i , E F --E i , E 2 --E 1 , m * and t q are in good agreement with those determined from Shubnikov-de Haas effect in magnetoresistance. It is shown that the experimental technique employed in the current study is equally successful in determining the effective scattering mechanisms in highly-degenerate 2D structures at low temperatures. The results obtained for transport-to-quantum lifetime ratio suggest that the scattering of electrons in the first subband of modulation-doped In 0.53 Ga 0.47 As/ In 0.52 Al 0.48 As heterojunctions is, on average, forward displaced in momentum space, while the scattering of electrons in the second subband contains some contribution from large-angle scattering.

Electron and hole energy relaxation rates in GaInNAs/GaAs quantum wells via deformation potential and piezoelectric scattering

Physica Status Solidi (b)

Ardalı

2012

The two‐dimensional (2D) electron and hole energy relaxation associated with acoustic phonon emission in n‐ and p‐type modulation doped Ga0.7In0.3NyAs1–y/GaAs quantum wells has been investigated experimentally using Shubnikov‐de Haas (SdH) effect measurements performed as a function of lattice temperature and applied electric field. Nitrogen concentration dependence of the effective mass and quantum lifetime of the 2D electrons in the n‐type samples have been determined from the temperature and magnetic field dependencies of the amplitude of SdH oscillations, respectively. The in‐plane effective mass of the 2D electrons increases when the nitrogen mole fraction is increased from y = 0.004 to 0.010 but remains the same when it is increased to y = 0.015. The values obtained for quantum lifetime suggest that interface roughness is the dominating scattering mechanism in n‐type Ga0.7In0.3NyAs1–y/GaAs quantum wells. The electron temperature (Te) of hot electrons and the hole temperature (Th) of hot holes have been obtained from the lattice temperature (TL) and applied electric field dependencies of amplitude of SdH oscillations. The experimental results for the electron/hole temperature dependence of power loss are compared with the current theoretical models for power loss in 2D semiconductors, which include both piezoelectric and deformation‐potential scattering. For n‐type samples, the power loss from the electrons is found to be proportional to (T–T) with γ in the range from 3.48 to 4.66, indicating that the energy relaxation of electrons is due to acoustic phonon emission via unscreened piezoelectric interaction. For the p‐type sample, the power loss is approximately proportional to (T–T). This behavior is in accord with the theoretical predictions for the variation of power loss with hole temperature for a 2D hole gas in the equipartition regime.