a family of high speed transistors and optoelectronic devices are obtained on a monolithic substrate by adding two sheets of planar doping together with a wideband cladding layer to the top of a pseudomorphic high electron mobility transistor structure . the two sheets are of the same polarity which is opposite to the modulation doping of the phemt and they are separated by a lightly doped layer of specific thickness . the combination is separated from the phemt modulation doping by a specific thickness of undoped material . the charge sheets are thin and highly doped . the top charge sheet achieves low gate contact resistance and the bottom charge sheet defines the capacitance of the field - effect transistor with respect to the modulation doping layer of the phemt . the structure produces a pnp bipolar transistor , enhancement and depletion type fets , a vertical cavity surface emitting laser , and a resonant cavity detectors . β