Consider a two dimensional electron structure concentration

Consider a two dimensional electron structure concentration four an n-ALGa As - intrinsic GA A_3 heterojunction. Consider N - AL_0.3 G_a_0.7 As doped to 10^+18[cm^-3] and having a thickness of 500[R]. Assume an undoped space layer of 20[A]. let_B = 0.85[v] and (Delta E_c/q) = 0.22[v]. the relative dielectric constant of. AL_0.3 Ga_0.7 As is_N = 12.2. Determine: the two - dimensional electron concentration, n_s. the type of the transistor?

Solution

4.2)

for the above question given,that the transistor used for a two dimensional electron concentration is a High-electron-mobility transistor, also known as heterostructure FET ormodulation-doped FET, is a field-effect transistor incorporating a junction between two materials with different band gaps (i.e. a heterojunction) as the channel instead of a doped region (as is generally the case for MOSFET). A commonly used material combination is GaAs with AlGaAs, though there is wide variation, dependent on the application of the device. Devices incorporating more indium generally show better high-frequency performance, while in recent years, gallium nitride HEMTs have attracted attention due to their high-power performance. HEMT transistors are able to operate at higher frequencies than ordinary transistors, up to millimeter wavefrequencies, and are used in high-frequency products such as cell phones, satellite television receivers, voltage converters, andradar equipment.