Vertical tunnel field-effect transistors (TFETs) in which the gate field is aligned with the tunneling direction have been fabricated using a novel gate-recess process, resulting in record on-current. The tunnel junction consists of InAs/GaSb with a broken band alignment. The gate-recess process results in low drain contact and access resistances; together with the favorable broken gap heteroju...

A compact cryogenic Kerr microscope for operation in the small volume of high-field magnets is described. It is suited for measurements both in Voigt and Faraday configurations. Coupled with a pulsed laser source, the microscope is used to measure the time-resolved Kerr rotation response of semiconductor microstructures with approximately 1 mum spatial resolution. The microscope was designed to...

The price of energy to separate tightly bound electron-hole pair (or charge-transfer state) and extract freely movable charges from low-mobility materials represents fundamental losses for many low-cost photovoltaic devices. In bulk heterojunction (BHJ) polymer solar cells (PSCs), approximately 50% of the total efficiency lost among all energy loss pathways is due to the photogenerated charge c...

We present laser beam astigmatism results obtained by Near-field Scanning Optical Microscopy. Measurements made with this technique on the high reflecting facet of a Graded Index Separate Confinement Heterojunction laser diode indicate the lateral beam waist is outside of the device structure, seemingly in contradiction to far-field measurements made on the low reflecting output facet of the de...

Strained InGaN layers grown on a c-plane sapphire is known to have strong spontaneous and piezoelectric polarization field, where the discontinuity of polarization at heterojunction is to induce bounded surface charges [1]. This polarization-related phenomenon can affect the internal electric field of active region and induce the quantum-confined stark effect (QCSE) at quantum well. QCSE result...

Terahertz detection capability of an n-type heterojunction interfacial work function internal photoemission (HEIWIP) detector is demonstrated. Threshold frequency, f0, of 3.2 THz (93 lm) was obtained by using n-type GaAs emitter doped to 1 · 10 cm 3 and Al0.04Ga0.96As single barrier structure. The detector shows a broad spectral response from 30 to 3.2 THz (10–93 lm) with peak responsivity of 6...