Abstract
We present experimental and theoretical characterization of InP-based heterostructure integrated thermionic (HIT) coolers. In particular, the effect of doping on overall device performance is characterized. Several thin-film cooler devices have been fabricated and analyzed. The coolers consist of a 1μm thick superlattice structure composed of 25 periods of InGaAs well and InGaAsP (λgap ≈ 1.3μm) barrier layers 10 and 30nm thick, respectively. The superlattice is surrounded by highly-doped InGaAs layers that serve as the cathode and anode. All layers are lattice-matched to the n-type InP substrate. N-type doping of the well layers varies from 1.5×1018cm−3 to 8×1018 cm−3 between devices, while the barrier layers are undoped. Device cooling performance was measured at room-temperature. Device current-versus-voltage relationships were measured from 45K to room-temperature. Detailed models of electron transport in superlattice structures were used to simulate device performance. Experimental results indicate that low-temperature electron transport is a strong function of well layer doping and that maximum cooling will decrease as this doping is increased. Theoretical models of both I-V curves and maximum cooling agree well with experimental results. The findings indicate that low-temperature electron transport is useful to characterize potential barriers and energy filtering in HIT coolers.
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Singh, R., Vashaee, D., Zhang, Y. et al. Experimental Characterization and Modeling of InP-based Microcoolers. MRS Online Proceedings Library 793, 87–93 (2003). https://doi.org/10.1557/PROC-793-S11.4
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DOI: https://doi.org/10.1557/PROC-793-S11.4