Observation of Intersubband Absorption in Boron δ-Doped Si Layers

1991 ◽  
Vol 220 ◽  
Author(s):  
J. S. Park ◽  
R. P. G. Karunasiri ◽  
K. L. Wang ◽  
Y. J. Mii ◽  
J. Murray
Keyword(s):  
Quantum Wells ◽  
Infrared Absorption ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Many Body ◽  
Ir Detectors ◽  
Boron Doped ◽  
Peak Energy ◽  
Ftir Spectrometer ◽  
Experimental Values

ABSTRACTStrong hole intersubband infrared absorption in δ-doped Si multiple quantum wells is observed. The structures consist of 10 periods of boron doped Si quantum wells and undoped Si barriers. Near 100 % infrared absorption is measured by FTIR spectrometer using waveguide structures. Absorption peaks ranging between 3–7 μm are measured, and these peaks can be tuned by varying the doping concentration in the δ-doped layer. Polarization dependence has been verified to agree with the intersubband selection rule. The estimated peak energy positions using a self-consistency calculation are considerably lower than experimental values, probably due to a large exchange energy of many body effects. This observation suggests multiple quantum well IR detectors using Si- technology.

Low Temperature Infrared Measurements and Photo-Induced Persistent Changes of Intersubband Transitions in GaAs/AlGaAs Multiple Quantum Wells.

1990 ◽  
Vol 216 ◽  
Author(s):  
B. Dischler ◽  
J.D. Ralston ◽  
P. Koidl ◽  
P. Hiesinger ◽  
M. Ramsteiner ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Infrared Absorption ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Intersubband Transition ◽  
Thermal Regeneration ◽  
Quantum Well Structures ◽  
Hall Measurements ◽  
Si Doping ◽  
Infrared Measurements

ABSTRACTUtilizing infrared absorption and Hall measurements, a detailed study is presented of the temperature dependence (10 K < T < 300 K) of the intersubband transition and related doping behaviour in GaAs/Al0.32Ga0.68As multiple quantum well structures with Si doping concentrations between 1×1018 and 8×1018 cm−3 in the quantum wells. The intersubband transition frequency increases with decreasing temperature, which can be adequately modelled by considering the different effective masses and the thermal populations of the two electron subbands. This model also accounts for the decrease in linewidth of the infrared absorption resonance upon cooling. In Hall measurements a persistent photo-induced decrease in the free electron concentration within the GaAs quantum wells is observed for Si doping levels exceeding 5×1018 cm−3. Corresponding decreases are observed both in the integrated absorption and the absolute frequency of the intersubband transition, the latter arising from a reduction in the depolarization shift. The spectral dependence of the photo-induced changes over the energy range 1.2 eV < hν < 2.5 eV, along with thermal regeneration over the temperature range 70 K < T < 150 K, have been studied.

Similarities in the Optical Properties of Hexagonal and Cubic InGaN Quantum Wells

2001 ◽  
Vol 693 ◽  
Author(s):  
S. F. Chichibu ◽  
M. Sugiyama ◽  
T. Onuma ◽  
T. Kuroda ◽  
A. Tackeuchi ◽  
...  
Keyword(s):  
Optical Properties ◽  
Quantum Wells ◽  
Multiple Quantum Well ◽  
Intrinsic Property ◽  
Multiple Quantum ◽  
Time Resolved ◽  
Exciton Localization ◽  
Peak Energy ◽  
Stretched Exponential Decay ◽  
Ingan Quantum Wells

AbstractOptical properties of fully-strained wurtzite and zincblende InxGa1-xN/GaN multiple quantum well (MQW) structures were compared to discuss the origin of exciton localization. In contrast to the hexagonal InGaN MQWs, the photoluminescence (PL) peak energy of cubic InGaN MQWs showed a moderate blueshift with decreasing well thickness, L, and low-temperature PL decay time of the cubic MQWs did not depend strongly on L. The results imply that the wavefunction overlap in cubic InGaN MQWs was not reduced compared to the hexagonal ones, since they do not suffer from the electric field normal to the QW plane due either to spontaneous or piezoelectric polarization. Both MQWs exhibited a large and composition-dependent bandgap bowing, and time-resolved PL (TR-PL) signals showed a stretched-exponential decay even at room temperature. The exciton localization is considered to be an intrinsic property of InGaN.

scholarly journals Luminescent Characteristics of InGaAsP/InP Multiple Quantum Well Structures by Impurity-Free Vacancy Disordering

2001 ◽  
Vol 692 ◽  
Author(s):  
J. Zhao ◽  
X. D. Zhang ◽  
Z. C. Feng ◽  
J. C. Deng ◽  
P. Jin ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Band Gap ◽  
Annealing Temperature ◽  
Multiple Quantum Well ◽  
Blue Shift ◽  
Multiple Quantum ◽  
Quantum Well Structures ◽  
Cladding Layer ◽  
Cap Layer ◽  
Free Vacancy

AbstractInGaAsP/InP multiple quantum wells have been prepared by Impurity-Free Vacancy Disordering (IFVD). The luminescent characteristics was investigated using photoluminescence (PL) and photoreflectance (PR), from which the band gap blue shift was observed. Si3N4, SiO2 and SOG were used for the dielectric layer to create the vacancies. All samples were annealed by rapid thermal anne aling (RTA). The results indicate that the band gap blue shift varies with the dielectric layers and annealing temperature. The SiO2 capping was successfully used with an InGaAs cladding layer to cause larger band tuning effect in the InGaAs/InP MQWs than the Si3N4 capping with an InGaAs cladding layer. On the other hand, samples with the Si3N4-InP cap layer combination also show larger energy shifts than that with SiO2-InP cap layer combination.

Intersubband Infrared Absorption in a GaAs/Al0.3Ga0.7As Multiple Quantum Well

1992 ◽  
pp. 287-297
Author(s):  
M. O. Manasreh ◽  
F. Szmulowicz ◽  
T. Vaughan ◽  
K. R. Evans ◽  
C. E. Stutz ◽  
...  
Keyword(s):  
Quantum Well ◽  
Infrared Absorption ◽  
Multiple Quantum Well ◽  
Multiple Quantum

scholarly journals Piezoelectric Level Splitting in GaInN/GaN Quantum Wells

1999 ◽  
Vol 4 (S1) ◽  
pp. 357-362
Author(s):  
C. Wetzel ◽  
T. Takeuchi ◽  
H. Amano ◽  
I. Akasaki
Keyword(s):  
Quantum Wells ◽  
Electric Fields ◽  
High Performance ◽  
Stark Effect ◽  
Electronic Band Structure ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Large Set ◽  
Electronic Band ◽  
Level Splitting

Identification of the electronic band structure in AlInGaN heterostructures is the key issue in high performance light emitter and switching devices. In device-typical GaInN/GaN multiple quantum well samples in a large set of variable composition a clear correspondence of transitions in photo- and electroreflection, as well as photoluminescence is found. The effective band offset across the GaN/GaInN/GaN piezoelectric heterointerface is identified and electric fields from 0.23 - 0.90 MV/cm are directly derived. In the bias voltage dependence a level splitting within the well is observed accompanied by the quantum confined Stark effect. We furthermore find direct correspondence of luminescence bands with reflectance features. This indicates the dominating role of piezoelectric fields in the bandstructure of such typical strained layers.

Optical properties of GaN Photonic Crystal Membrane Nanocavities at Blue Wavelengths

2005 ◽  
Vol 892 ◽  
Author(s):  
Yong-Seok Choi ◽  
Cedrik Meier ◽  
Rajat Sharma ◽  
Kevin Hennessy ◽  
Elaine D. Haberer ◽  
...  
Keyword(s):  
Optical Properties ◽  
Photonic Crystal ◽  
Quantum Wells ◽  
Multiple Quantum Well ◽  
Light Extraction ◽  
Design Parameters ◽  
Multiple Quantum ◽  
Membrane Structures ◽  
High Q ◽  
Q Factors

AbstractWe have investigated the design parameters for high-Q photonic-crystal (PC) bandgap modes in the emission wavelengths of InGaN/GaN multiple quantum wells. We demonstrate experimental schemes to realize 2D triangular-lattice PC membrane structures, which is essential to obtain photonic bandgap (PBG) modes, and the optical properties of L7 membrane nanocavities that consist of seven missing holes in the Γ-K direction. L7 cavities show pronounced resonances with Q factors of 300 to 800 in the PBG as well as the enhancement of light extraction of the broad InGaN/GaN multiple-quantum-well emission by the 2D PBG.

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.

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