Adhesion energy and shape of nanogap InP/InGaAs microcantilevers

The adhesion energy is measured between InGaAs quantum wells that have collapsed across a 120 nm airgap in a InP/InGaAs heterostructure. The method relies on measuring the unadhered length and shape of collapsed microcantilevers with optical interferometry. The adhesion energy is found to be 72 plusmn 16 mJm^-2. Since the airgap is much smaller than has been measured previously, the influence of van-der-Waals forces across the gap was included in theoretical modeling. It was found that the forces should not cause significant deviation from the standard adhesion models unless the adhesion energy drops below 25 mJm^-2.