Investigation of the doping and Stark effects on the band structure and optical absorption of 1.55 μm GaNAsBi/GaAs MQWs (original) (raw)
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Materials Science in Semiconductor Processing, 2014
Band structures of n-i doped lattice-matched GaNAsBi/GaAs quantum wells are studied theoretically using a self-consistent calculation (based on the envelop function formalism) combined with the 16-band anti-crossing model. Operating at 1.55 μm, these QWs can represent active zones of temperature-insensitive optoelectronic device applications intended for optical fiber communications. We have calculated physical parameters of the structures such as the confining potential profiles, the Fermi level, the subband energies and their corresponding wavefunctions as well as the oscillator strength of interband transitions, the subband occupations, and the confined electrons density distributions. Finally, the absorption coefficient spectra of GaNAsBi-based QWs are also computed.
ERDD, 2019
We investigated the optical absorption of n-doped GaN0.38yAs1-1.38ySby/GaAs quantum wells (QWs) using a self-consistent calculation combined with the 16-band anti-crossing model. GaNAsSb material seems to be a potential alternative for GaAs-based photodetectors operating at 0.8-1 eV energy range. The increase of the well width from 4 to 10 nm in GaN0.38yAs1-1.38ySby/GaAs QWs caused a red-shift of the fundamental transition energy accompanied with a significant decrease of the absorption coefficient. The wavelength emission of the studied QWs achieved the values 0.8 and 0.95 eV for specific values of Sb composition. A rise of doping density induced an increase of. The Stark effect on energy and was also discussed. Additionally, was adjusted in order to obtain the energies 0.8 and 0.95 eV of the electrically polarized GaNAsSb/GaAs QWs. Keywords-GaNAsSb/GaAs QWs; Absorption coefficient; n doping; Stark effect; energy range 0.8-1 eV.
Carriers confinement study of GaNAsBi/GaAs QWs emitting at 1.3 and 1.55 μm
Semiconductors, 2015
Band structures of GaN 0.58y As 1-1.58y Bi y /GaAs quantum wells (QWs) were studied using the band anticrossing model and the envelope function approximation. The confined states energies and the oscillator strengths of interband transitions were determined for well widths L W and Bi composition y varying in the range of 4-10 nm and 0-0.07 respectively. The emissions 1.3 and 1.55 µm were reached for specific couples (L W , y). The band anticrossing effect on the in plane carriers effective mass has been investigated at k = 0. The absorbance spectra were calculated for QWs operating at 1.3 and 1.55 µm.
MATEC Web of Conferences, 2020
In this paper, we theoretically investigate the impacts of Internal well composition, size and impurity's position on the inter valence-conduction bands and intra conduction band optical absorption in GaN/(In,Ga)N/GaN hetero-structure. Based on the numerically finite element method (FEM), the impurity's related Schrödinger equation is solved for the finite potential barrier considering the dielectric constant and effective-mass mismatches between the well and its surrounding matrix. Our results show that the absorption is strongly governed by the dipole matrix element and initial and final implied states transition energies. For a fixed barrier width, the absorption spectra are found red-shifted (blue-shifted) with increasing the well width (In-concentration). It is also shown that the impurity's absorption phenomenon is more pronounced for the off-center case compared to the on-center one. We conclude that the proper control of these parameters is required to best under...
Progress In Electromagnetics Research M, 2014
Selective wavelength tuning of multiple quantum well based infrared photodetector is achieved by non-uniform doping distribution as well as dimensional variation in the structure. Result is obtained from the computation of the intersubband transition energy through self-consistent solution of the Poisson's and Schrödinger equations with appropriate boundary conditions. Absorption coefficient is estimated in presence of external electric field applied along the direction of confinement. Suitable choice of structural parameters is required to tailor the peak position of absorption spectra for application in the infrared range as optical receiver.
MBE growth of AlN/GaN-based photovoltaic intersubband photodetectors
physica status solidi (a), 2008
1 Introduction Intersubband (ISB) transitions in semiconductor quantum wells (QWs) have proven their capability for optoelectronics the mid-and far-infrared spectral regions. The extension of ISB optoelectronics towards the near infrared spectral region is interesting for the development of ultrafast photonic devices for optical telecommunication networks. Material systems with large enough conduction band offsets to accommodate ISB transitions at these relatively short wavelengths (1.3 µm, 1.55 µm) include InGaAs/AlAsSb, (CdS/ZnSe)/BeTe, and GaN/Al(Ga)N QWs. In the case of III-nitride heterostructures, their conduction-band offset − about 1.75 eV for the GaN/AlN system [1] − is large enough to develop ISB devices operating in the fibre-optics transmission windows at 1.3 µm and 1.55 µm. A specific advantage of III-nitrides is their extremely short ISB absorption recovery times (~150-400 fs [2]) due to the strong electron-phonon interaction in these materials, which open the way for devices operating in the 0.1-1 Tbit/s bit-rate regime. Furthermore, the remote lateral valleys lie very high in energy (>2 eV) above the Γ valley, which is a key feature to achieve ISB lasing. Finally, devices would profit from other advantages of nitride technology, such as high power handling capabilities and chemical and thermal robustness.
Journal of Applied Physics, 2008
We have studied the effect of growth and design parameters on the performance of Si-doped GaN/AlN multiquantum-well ͑MQW͒ structures for intersubband optoelectronics in the near infrared. The samples under study display infrared absorption in the 1.3-1.9 m wavelength range, originating from the photoexcitation of electrons from the first to the second electronic level in the QWs. A commonly observed feature is the presence of multiple peaks in both intersubband absorption and interband emission spectra, which are attributed to monolayer thickness fluctuations in the quantum wells. These thickness fluctuations are induced by dislocations and eventually by cracks or metal accumulation during growth. The best optical performance is attained in samples synthesized with a moderate Ga excess during the growth of both the GaN QWs and the AlN barriers without growth interruptions. The optical properties are degraded at high growth temperatures ͑Ͼ720°C͒ due to the thermal activation of the AlN etching of GaN. From the point of view of strain, GaN/AlN MQWs evolve rapidly to an equilibrium average lattice parameter, which is independent of the substrate. As a result, we do not observe any significant effect of the underlayers on the optical performance of the MQW structure. The average lattice parameter is different from the expected value from elastic energy minimization, which points out the presence of periodic misfit dislocations in the structure. The structural quality of the samples is independent of Si doping up to 10 20 cm −3 . By contrast, the intersubband absorption spectrum broadens and blueshifts with doping as a result of electron-electron interactions. This behavior is independent of the Si doping location in the structure, either in the QWs or in the barriers. It is found that the magnitude of the intersubband absorption is not directly determined by the Si concentration in the wells. Instead, depending on the Al mole fraction of the cap layer, the internal electric field due to piezoelectric and spontaneous polarization can deplete or induce charge accumulation in the QWs. In fact, this polarization-induced doping can result in a significant and even dominant contribution to the infrared absorption in GaN/AlN MQW structures.