Fig. 3From: The Role of Air Adsorption in Inverted Ultrathin Black Phosphorus Field-Effect Transistors a Transfer characteristic of back-gate inverted BP FET after annealing about 5 min, p-doping is weaker than n-doping. b Transfer characteristic of back-gate inverted BP FET after annealing about 10 min, p-doping enhances slowly while n-doping fades away. c Transfer characteristic of back-gate inverted BP FET after annealing about 5 h, n-doping reduces to near zeroBack to article page