$1-$ Specify the semiconductor $($substrate$)$ type used in this device. Explain.

$2-$ In what region of operation is this device in$?$ Explain.

$3-$ Do you need to apply positive or negative voltage at the gate to operate in this given region? Explain.

$4-$ Draw the energy band diagram of the semiconductor for the two other regions of operation. Label the energy levels and the applied voltage $($negative or positive$)$ at the gate.

$5-$ You were asked to change the region of operation of the device from the one shown to either one of the other two regions. Pick either one of the two other regions and explain what you would change.