Effects of Si-doping in the barriers on the recombination dynamics in In0.15Ga0.85N/In0.015Ga0.985N quantum wells

Abstract

A systematic study of time-resolved photoluminescence spectra from In0.15Ga0.85N/In0.015Ga0.985N quantum wells (QWs) with different Si-doping concentration in the barriers has been carried out. The 10 K recombination lifetimes in the QWs depend strongly on the Si-doping in the barriers, decreasing from ∼80 to ∼20 ns as the Si-doping level increases from 2×1018 to 1×1019 cm−3. The separation between the spontaneous and stimulated emission (SE) peaks and a shift of the emission peak to longer wavelengths with delay time after a pulsed excitation decrease with increasing Si doping. The increased recombination rate, the decrease of peak shift with delay time, and the reduced separation between the spontaneous and SE peaks with increasing Si doping are attributed to the screening of piezoelectric field by carriers originated from Si-doped barriers.

Influence of quantum well inhomogeneities on absorption, spontaneous emission, photoluminescence decay time, and lasing in polar InGaN quantum wells emitting in the blue-green spectral region

“…2(a)] was obtained at the assumption that the built-in electric field inside the QW system results from the piezoelectric and spontaneous polarizations in this system [15,16] with the appropriate periodic boundary conditions [28] (this situation is characterized by a step-like difference in the total polarization at QW interfaces P ). It should be noted that the internal electric field, which results from polarization effects, can be partially screened in our samples because of Si doping in InGaN barriers [29][30][31]. It means that the real built-in electric field is smaller than the electric field corresponding to 100 % P in Fig.…”

Influence of electron distribution on efficiency droop for GaN-based light emitting diodes

“…While, for different InGaN quantum barriers, the growth temperature were kept at the same 800 o C but with different TMIn flows at 0, 32, and 160 sccm, respectively. Meantime, in order to screen the piezoelectric field, all of the barriers were Si-doped [18]. Finally, 100 nm thick Mg-doped p-GaN layers were deposited.…”

Mechanisms for photon-emission enhancement with silicon doping in InGaN/GaN quantum-well structures

“…In the past, the abovementioned optical phenomena observed in barrier silicon-doped samples were usually attributed to carrier screening of the piezoelectric fields upon silicon doping. [3][4][5] However, the comparison between the results of samples B and C indicates that the carrier-screening effect may play a minor role in reducing QCSE in our samples. This is because the reduction of QCSE is less significant in the well-doped sample, in which more carriers are expected in the designated well layers (and inside the clusters) for piezoelectric-field screening.…”

“…The blueshift (73 meV at 10 K) of the PL peak in sample B compared with the undoped sample (A) has been widely observed. [3][4][5] The PL peaks of the well-doped sample (C) approximately coincide with those of the undoped sample (A), except the small redshifts below 80 K and above 200 K. All the curves in Fig. 4 show S-shaped variations of the PL peak, which is typical behavior of such clustered and strained structures.…”

“…Typically, with increasing silicon-doping concentration, particularly doping in barriers, the following phenomena were observed: (1) the photoluminescence (PL) peak blue shifted, (2) the Stokes shift (SS) decreased, (3) the PL decay time reduced, and (4) the PL intensity increased. [1][2][3][4][5][6] Such variations in optical properties were usually attributed to the screening of the quantum-confined Stark effect (QCSE) [3][4][5] because of the doped carriers. In other words, the piezoelectric field was effectively reduced with silicon doping through carrier screening.…”