Band gap dependent thermophotovoltaic device performance using the InGaAs and InGaAsP material system

Abstract

Thermophotovoltaic cells with a range of band gaps are modeled under a variety of illumination conditions, including a range of source temperatures and a variable degree of spectral control. Thus, the balance between the requirements of high power densities and high efficiencies can be investigated. The influence of elevated cell temperatures, cell cooling, Auger recombination, and series resistances have been included, and all weight the optimum band gap thermophotovoltaic cell toward higher band gaps than the ∼0.5–0.6 eV conventional optimum. The cells have been modeled using fundamental physical parameters from the InGaAs and InGaAsP material system which accurately reproduce reported device performance and allow a comparison to theoretical limits.

Interband casade thermophotovoltaic devices with Type-II superlattice absorbers of ∼0.4 eV bandgap

“…The basic design of a single IC PV stage is similar to those of our previously reported devices [3][4]. Each stage had a SL absorber sandwiched between an electron barrier, consisting of GaSb/AlSb quantum wells (QWs), and a hole barrier, consisting of InAs/Al(In)Sb QWs.…”

“…By doing this, the power loss from the contact resistance can be reduced. This type of loss is predicted to be fairly high in narrow-bandgap materials [4]. This ability to reduce the contact power loss should be especially useful for TPV and laser power-beaming applications, where the incident light intensities (and by extension the resulting cell currents) are quite high.…”

Low Bandgap InAs-Based Thermophotovoltaic Cells for Heat-Electricity Conversion

“…23 Epitaxial layers of unintentionally doped InAs and p-type Zn-doped $1 9 10 18 cm À3 , quaternary InAsSbP were grown nominally latticematched onto n-type, 2 9 10 18 cm À3 InAs (100) substrates by conventional LPE using a horizontal sliding boat technique. Growth was implemented from In-rich melts at temperatures within the interval of 570-580°C based on our previous work, 10 using supercooling, DT $ 3°C. The alloy composition of the quaternary alloy as determined by energy dispersive x-ray analysis was found to be InAs 0.61 Sb 0.13 P 0.26 .…”

“…2, this is primarily a result of the high intrinsic carrier concentration in InAs ($10 15 cm À3 ) and the minority carrier lifetime (diffusion length). 10 …”

Low bandgap mid-infrared thermophotovoltaic arrays based on InAs

“…The optimum TPV cell bandgap depends on the emitter blackbody temperature, and following the thermodynamic detailed balance model, 1 in the ideal case where radiative recombination is dominant, the maximum TPV cell efficiency is ~ 35% for source temperatures between 1200 -2500 K, such that the optimum bandgap falls in the range 0.2 -0.5 eV. 2 To date previous work has concentrated on TPV devices matched to high temperature sources using semiconductors with larger bandgaps such as silicon (E g =1.1 eV), InGaAs 3 on InP (typically E g = 0.5-0.73 eV, but which is limited by lattice mismatch to the higher bandgaps), or InGaAsSb on GaSb (constrained to E g = 0.5 eV by a miscibility gap). There have been some studies of the development and characterization of InAs based diodes for lower temperature TPV applications, but, these reports concern mainly epitaxial growth and characterisation of individual elements 4,5 .…”