Tunnel radiation in the luminescence spectra of GaN-based heterostructures

2002 ◽  
Vol 743 ◽  
Author(s):  
A. E. Yunovich ◽  
V. E. Kudryashov ◽  
A. N. Turkin ◽  
M. Leroux ◽  
S. Dalmasso
Keyword(s):  
Quantum Wells ◽  
Electric Fields ◽  
Spectral Band ◽  
Luminescence Spectra ◽  
Energy Diagram ◽  
Radiation Spectra ◽  
Piezoelectric Fields ◽  
High Electric Fields ◽  
Tunnel Effects ◽  
Ingan Quantum Wells

ABSTRACTTunnel effects in luminescence spectra and electrical properties of LEDs based on InGaN/GaN-heterostructures made by different technological groups were studied. The tunnel radiation in a spectral region of 1.9 - 2.7 eV predominates at low currents (J<0.2 mA). The position of the tunnel luminescence maximum orħħωmax is approximately equal to the voltage U, orħħωmax = eU. The low energy spectral band is described by the theory of tunnel radiative recombination. Tunnel recombination mechanisms in GaN-based heterostructures are caused by high electric fields in the active InGaN/GaN - MQW layers. The energy diagram of the structures is analyzed. The probability of tunnel radiation is higher due to piezoelectric fields in InGaN quantum wells. The tunnel radiation spectral band was not observed in the more effective LEDs with modulated doped MQWs. The spectra of GaN-based LEDs are compared with tunnel radiation spectra of GaAs-, InP- and GaSb- based LEDs. The equation: orħħωmax = eU describes experimental data in various semiconductors in the range 0.5–2.7 eV.

Tunnel Effects in Luminescence Spectra of InGaN/AlGaN/GaN Light-Emitting Diodes

1996 ◽  
Vol 449 ◽  
Author(s):  
A. E. Yunovich ◽  
A. N. Kovalev ◽  
V. E. Kudryashov ◽  
F. I. Manyachin ◽  
A. N. Turkin ◽  
...  
Keyword(s):  
Spectral Band ◽  
Luminescence Spectra ◽  
Energy Diagram ◽  
Light Emitting ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Recombination Current ◽  
Blue Line ◽  
Tunnel Effects

ABSTRACTTunnel effects in luminescence spectra and electrical properties of blue InGaN/AlGaN/GaN LEDs were studied. The tunnel radiation in a spectral region of 2.1–2.4 eV predominates at low currents (J<0.2 mA). The role of tunnel effects grows as the maximum of the main blue line in LEDs is shifted to short wavelengths. The position of the tunnel maximum ћωmax is approximatly proportional to the voltage eU. The spectral band is described by the theory of tunnel radiative recombination. Current-voltage characteristics have a tunnel component at low direct and reverse currents. The distribution of charged impurities was received from dynamic capacitance measurements. There are charged layers at heterointerfaces and adjacent compensated layers in the structures. There is a high electric field in the active layer. The energy diagram is analysed.

Electrical Properties and Luminescence Spectra of Light-Emitting Diodes with Modulated Doped InGaN/GaN Quantum Wells

2002 ◽  
Vol 722 ◽  
Author(s):  
A.E. Yunovich ◽  
S.S. Mamakin ◽  
M.V. Lomonosov ◽  
F.I. Manyakhin ◽  
A.B. Wattana ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Light Emitting Diodes ◽  
Debye Length ◽  
Green Light ◽  
Luminescence Spectra ◽  
Multiple Quantum ◽  
Energy Diagram ◽  
Light Emitting ◽  
Charge Distributions ◽  
Piezoelectric Fields

AbstractCharge distributions N(z) and electroluminescence spectra of blue and green light-emitting diodes (LEDs) based on InGaN/AlGaN/GaN heterostructures with multiple quantum wells. MQWs were modulated doped by Si donors in GaN barriers, electrons from donors being in InGaN wells. N(z) were determined using dynamical capacitance (C-V) method. Acceptor and donor concentrations near the p-n- junction were approximately NA ≥1.1019 cm-3 >> ND ≥ 1.1018 cm-3. Functions N(z) have periodic maxima and minima; their number was 4 and a period of 10 %15 nm, according to the details of growth. The extrema reflect charge distributions in MQWs on the n-side of the junctions with accuracy in z of the order of the Debye length (2-3 nm). An energy diagram of the structures is calculated according these measurements. Shifts of spectral maxima with current (J = 10-6 – 3.10-2 A) for these LEDs are comparatively low (3-12 meV for blue LEDs and 20-50 meV for green ones), much less than for previously studied green LEDs (up to 150 meV). This behavior is explained by screening of piezoelectric fields by electrons in the wells. Quantum efficiency versus current is correlated with N(z) distributions and currentvoltage characteristics of the LEDs.

scholarly journals Photo- and cathodoluminescence investigations of piezoelectric GaN/AlGaN quantum wells

2000 ◽  
Vol 639 ◽  
Author(s):  
E.M. Goldys ◽  
M. Godlewski ◽  
M.R. Phillips ◽  
A.A. Toropov
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Electric Fields ◽  
Free Exciton ◽  
Multiple Quantum Well ◽  
Depth Profiling ◽  
Multiple Quantum ◽  
Recombination Mechanism ◽  
Decay Times ◽  
Piezoelectric Fields

ABSTRACTWe have examined multiple quantum well AlGaN/GaN structures with several quantum wells of varying widths. The structures had strain-free quantum wells and strained barriers. Strong piezoelectric fields in these structures led to a large red shift of the PL emission energies and long decay times were also observed. While the peak energies could be modelled using the effective mass approximation, the calculated free exciton radiative lifetimes were much shorter than those observed in experiments, indicating an alternative recombination mechanism, tentatively attributed to localised excitons. Cathodoluminescence depth profiling revealed an unusually small penetration range of electrons suggesting that electron-hole pairs preferentially remain within the multiple quantum well region due to the existing electric fields. Spatial fluctuations of the cathodoluminescence intensity were also observed.

Photoluminescence study of undoped‐like GaAs/AlGaAs quantum wells in high electric fields

1993 ◽  
Vol 74 (2) ◽  
pp. 1188-1194
Author(s):  
Naoteru Shigekawa ◽  
Tomofumi Furuta ◽  
Kunihiro Arai ◽  
Masaaki Tomizawa
Keyword(s):  
Quantum Wells ◽  
Electric Fields ◽  
Photoluminescence Study ◽  
High Electric Fields

Electroluminescence Properties of InGaN/AlGaN/GaN Light Emitting Diodes with Quantum Wells

1998 ◽  
Vol 537 ◽  
Author(s):  
A.E. Yunovich ◽  
V.E. Kudryashov ◽  
A..N. Turkin ◽  
A.N. Kovalev ◽  
F.I. Manyakhin
Keyword(s):  
Quantum Wells ◽  
Large Scale ◽  
Light Emitting Diodes ◽  
Spectral Band ◽  
High Energy ◽  
Model Fit ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Wide Range ◽  
Tunnel Effects

AbstractElectroluminescence spectra of light-emitting diodes based on InGaN/AlGaN/GaN heterostructures with single and multiple quantum wells (QWs) are analyzed by models of radiative recombination in 2D-structures with band tails. Equations of the model fit spectra quite good in a wide range of currents. Parameters of the fit are discussed and compared for single and multiple QWs. Tunnel effects play a sufficient role in blue LEDs with single QWs at low currents; they can be neglected in LEDs with multiple QWs. A new spectral band was detected at the high energy side of the spectra of green LEDs with multiple QWs; it is attributed with large scale inhomogenities of In distribution in InGaN QWs.)

Photoluminescence from GaAs quantum wells under high electric fields

1986 ◽  
Vol 59 (11) ◽  
pp. 3925-3927 ◽  
Author(s):  
Janet L. Pan ◽  
Ralph A. Höpfel ◽  
Jagdeep Shah
Keyword(s):  
Quantum Wells ◽  
Electric Fields ◽  
High Electric Fields

Time Evolution of the Screening of Piezoelectric Fields in InGaN Quantum Wells

2006 ◽  
Vol 42 (12) ◽  
pp. 1202-1208 ◽  
Author(s):  
Iain H. Brown ◽  
Peter Blood ◽  
Peter M. Smowton ◽  
John D. Thomson ◽  
Santiago M. Olaizola ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Time Evolution ◽  
Piezoelectric Fields ◽  
Ingan Quantum Wells
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