n-type delta-doped quantum well lasers with extremely low transparency current density

Abstract

It is demonstrated that placing an n-type Te δ doping aside a single strained quantum well (QW) is an efficient way to control the initial carrier concentration in the QW and thus to lower transparency current density, Jtr, while preserving low internal losses. This is in contrast with uniform doping of the active area. Jtr of 11.3 A/cm<thin>2 and threshold current density of 54.4 A/cm2, which are both the lowest values reported to date for strained InxGa1−xAs/GaAs semiconductor lasers, were obtained. A somewhat higher injection efficiency is obtained when the energy levels are adjusted so that the electrons tunnel from the delta well directly into the QW.

Effects of doping in the active region of 630-nm band GaInP-AlGaInP tensile-strained quantum-well lasers

“…In this work, they are taken mainly from the data reported recently by Meney et al [17]. The and bandgaps of (Al Ga In P at 300 K are given by eV (9) eV (10) The band discontinuities for unstrained Ga In P in (Al Ga…”

“…However, the reduction of the threshold current is limited because the leakage current which plays an important part of the threshold current can not be suppressed effectively. A great reduction of the threshold current has been demonstrated by n-type doping in the active region of lasers in (In)GaAs-AlGaAs and InGaAsP-InP systems [6]- [9]. In addition, the n-type doped lasers have a shorter emission wavelength compared with that of undoped lasers [7].…”

Growth of Si delta-doped GaN by metalorganic chemical-vapor deposition

“…5,6 Moreover, the incorporation of delta doping into the laser structure of GaAs-based semiconductors has demonstrated some important improvements in the laser's performance, e.g., lowering the laser's transparency current density, increasing the modulation bandwidth of quantum well ͑QW͒ lasers and improving the temperaturerelated stability of QW lasers. 7,8 Recently, Kim et al have reported Si ␦-doped GaN layer growth with low-pressure metalorganic chemical-vapor deposition ͑MOCVD͒, and found that the delta doping of Si in GaN was very different from that of Si delta doping ͑␦ doping͒ in GaAs. 9 The Si delta-doping density increases and then decreases with an increase in delta-doping time, and the use of a postpurge step in the ammonia ambient reduces the Si delta-doping density.…”

n -type delta doped strained quantum well lasers for improved modulation bandwidth

“…The static effect of introducing n-type ␦ doping close to the QW active layer, was detailed in a recent publication. 9 The transparency current density, J tr , of a QW laser was shown to be halved. This effect stems from the higher initial electron population in the QW.…”

“…The absence of QW width dependence implies that this effect is a consequence of higher carrier concentration and a more efficient carrier injection into the QW, the same as for the lower J tr of the broad area lasers. 9 The strong dependence of MCEF on QW width is thought to be the result of another contribution of the ␦ doping, such as the differential gain.…”