scholarly journals Спектры остаточной фотопроводимости в гетероструктурах с квантовыми ямами HgTe/CdHgTe

2019 ◽  
Vol 53 (10) ◽  
pp. 1401
Author(s):  
К.Е. Спирин ◽  
Д.М. Гапонова ◽  
В.И. Гавриленко ◽  
Н.Н. Михайлов ◽  
С.А. Дворецкий
Keyword(s):  
Electric Field ◽  
Quantum Well ◽  
Carrier Concentration ◽  
Significant Role ◽  
General Trend ◽  
Persistent Photoconductivity ◽  
Free Carriers ◽  
Conductivity Type ◽  
P Type ◽  
Type Sample

Spectra of persistent photoconductivity (PPC) in HgTe/CdHgTe quantum well (QW) heterostructures of both n- and p-types have been investigated at T = 4.2 K. PPC is shown to be either positive (increase of carrier concentration in QW) or negative depending on a wavelength of the illumination. As a general trend, PPC maxima in n-type sample correspond to PPC minima in p-type samples and vice versa. It is discovered that in p-type samples the illumination with certain wavelengths results in the freezing out of free carriers in QWs but not in the conversion of the conductivity type. The latter indicates a significant role in the PPC mechanism of the built-in electric field that is switching off at the QW neutralization.

Strain-Induced Reconstruction of Impurity States in PbTe(Ga) Films

1993 ◽  
Vol 308 ◽  
Author(s):  
Boris A. Akimov ◽  
Ludmila I. Ryabova ◽  
Evgeniy I. Slynko
Keyword(s):  
Electric Field ◽  
Cooling Rate ◽  
Carrier Concentration ◽  
Low Temperatures ◽  
Free Carrier ◽  
Rapid Decrease ◽  
Laser Deposition ◽  
Persistent Photoconductivity ◽  
Impurity States ◽  
Heating Up

ABSTRACTn-type PbTe(Ga) films were grown by the laser deposition and the hot wall techniques on BaF2 substrates in <111> orientation. Doping results in the appearance of a high-ohmic state with nearly intrinsic free carrier concentration at low temperatures and activation character of conductivity at T∼300 K. Persistent photoconductivity has been observed at T < 100 K. In the hot wall-grown layers a new effect of bistability during the cooling-heating-cooling cycles has been found. On the first stage of the cycle a rapid decrease of resistivity (∼3 orders of magnitude) is observed at To∼50 K. The value of To changes by ± 15 K depending on the cooling rate. After a brief heating up to 80 K the subsequent cooling results in the high-ohmic state of the layer at the low temperatures. This state seems to be unstable. Relaxation to the low ohmic state can be accelerated by the application of electric field. The effect may be understood in terms of bistability of the Ga impurity charge state under the action of strain between the film and the substrate during the cooling-down process.

Effect of Cu doping on the electrical Properties of ZnTe by Vacuum Thermal Evaporation

2018 ◽  
Vol 31 (3) ◽  
pp. 20
Author(s):  
Sarmad M. M. Ali ◽  
Alia A.A. Shehab ◽  
Samir A. Maki
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Hall Effect ◽  
Carrier Concentration ◽  
Hall Mobility ◽  
Cu Doping ◽  
Before And After ◽  
Hall Effect Measurements ◽  
Evaporation Technique ◽  
P Type

In this study, the ZnTe thin films were deposited on a glass substrate at a thickness of 400nm using vacuum evaporation technique (2×10-5mbar) at RT. Electrical conductivity and Hall effect measurements have been investigated as a function of variation of the doping ratios (3,5,7%) of the Cu element on the thin ZnTe films. The temperature range of (25-200°C) is to record the electrical conductivity values. The results of the films have two types of transport mechanisms of free carriers with two values of activation energy (Ea1, Ea2), expect 3% Cu. The activation energy (Ea1) increased from 29meV to 157meV before and after doping (Cu at 5%) respectively. The results of Hall effect measurements of ZnTe , ZnTe:Cu films show that all films were (p-type), the carrier concentration (1.1×1020 m-3) , Hall mobility (0.464m2/V.s) for pure ZnTe film, increases the carrier concentration (6.3×1021m-3) Hall mobility (2m2/V.s) for doping (Cu at 3%) film, but  decreases by increasing Cu concentration.

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