As the etching instrument is designed for the use of 4 inch wafers, it is thus necessary to employ a carrier wafer to hold the easycleave samples. Carrier wafers (110, p-doped silicon, 4 inch, 500 nm thickness) were coated with a layer of positive photoresist (Olin OiR 908-35) that was spincoated at 4000 rpm and hard baked at 120 °C for 10 min. The photoresist prevents the carrier wafer from being etched, which avoids unwanted etching phenomena from a high silicon loading, and also ensures the reuseability of the wafer.