Interaction Strength between the Highly Localised Nitrogen States and the Extended Semiconductor Matrix States in GaInNAs

Abstract

Subject classification: 71.20.Nr; 78.55.Cr; S7.15 We have investigated the temperature dependence of photoluminescence (PL) emission from sequentially grown Ga 0.8 In 0.2 As and Ga 0.8 In 0.2 N 0.015 As 0.985 quantum wells between 2 K and room temperature. A significant reduction in the temperature dependence of the GaInNAs bandgap compared to nitrogen-free GaInAs is observed. The results are analysed using the band-anticrossing model, which accurately predicts the temperature dependence of the GaInNAs energy gap from the behaviour of the GaInAs energy gap. We also compare the band-anticrossing interaction parameter C NM used to fit our data with other published values for GaNAs and GaInNAs. The results suggest that C NM may not be independent of indium fraction.

Band structure calculations for dilute nitride quantum wells under compressive or tensile strain

“…Hypothesis (ii) has already been suggested by Potter et al [21]. A coupling parameter of V NM = 3.2 √ y eV has been determined by these authors for an In fraction in the well of x = 0.2.…”

Electron spin dynamics in GaAsN and InGaAsN structures

“…It has been shown that the introduction of nitrogen in GaAs or InGaAs strongly modifies the CB whereas it does not affect the Valence Band (VB). Substitutional nitrogen atoms form perturbed host states inside the CB, whereas small nitrogen aggregates form localised cluster states in the band gap [24][25][26]. For typical nitrogen content of the order of ~1%, there is a coexistence of localised states with delocalised ones; these two kinds of states overlapping in energy.…”

Boundary conditions for the electron wavefunction in GaInNAs-based quantum wells and modelling of the temperature-dependent bandgap

“…(This changes for V NM = 0, because different sites become indirectly coupled via the E M states.) If we now repeat the procedure described in the last paragraph for the case of two interfacing layers A and B, (12) holds for both sides of the interface separately, i.e. there are states with E = E A N and E = E B N , respectively.…”

“…It is well known that the incorporation of nitrogen into Ga(In)As quantum wells or bulk material leads to a reduced temperature dependence of the bandgap. Within the BAC model this quenching effect can be interpreted as a consequence of the repulsive interaction between the host conduction band E M and the nitrogen level E N (see, e.g., [2,3,11,12,14]). However, for a quantitative modelling of the thermally induced bandgap variation we need to know the temperature dependence of E N .…”

“…From an experimental point of view this result is confirmed by the fact that the BAC model has been applied very successfully so far. It has proven its ability to accurately describe not only the electronic states in bulk material but also in quantum well (QW) structures many times and can therefore be regarded as well established (see, e.g., [1][2][3][4][5][10][11][12][13][14] and references therein). However, the technologically important calculation of quantum well states usually requires a numerical diagonalization of the BAC Hamiltonian.…”