Current induced cooling in a metal/n-InAs structure

Abstract

This paper focuses on the specific features of an Ohmic contact on undoped n-InAs (n = 2 × 10¹⁶ cm⁻³) that could be used for temperature stabilization and/or temperature reduction in electronic devices, mainly operating in the 3–5 μm mid-IR range. This feature has been demonstrated in a 100 μm thick n-InAs slab with three unannealed Cr–Au–Ni–Au contacts formed via evaporation in vacuum. The I–V characteristics showed no deviation from Ohm's law in the temperature range 77–340 K, manifesting a contact resistance ranging from 3.6 × 10⁻⁵ to 7.2 × 10⁻⁵ Ω cm² at room temperature. The 2D thermal radiation distribution and the temperature distribution over the n-InAs surface opposite the contact side surface was obtained via a pre-calibrated IR microscope operating at a wavelength of 3 μm. The measurements revealed a current dependent temperature decline in the area adjacent to the negatively biased contact: at the applied power of 5 mW, cooling as strong as ΔT ≈ 1 K occurred at an ambient temperature of 340 K. The results show potential for the fabrication of heterostructures with a “built-in” cooler that is monolithically integrated with another electronic device.