GaSb/GaAlAsSb Heterostructure Photodiodes for the Near-IR Spectral Range

GaSb/GaAlAsSb uncooled photodiodes for the 1.1–1.85 μm spectral range are fabricated and studied. A unique method for the growth of GaSb from lead solution-melts makes it possible to obtain a low carrier concentration in the active region: n = 2 × 1015 cm–3. The capacitance of the photodiodes is 70–110 pF for a sensitive -area diameter of 300 μm and 150–250 pF for a diameter of 500 μm. The photodiodes are characterized by a high (for GaSb devices) spectral sensitivity Sλ = 0.95 A/W at the maximum, a relatively low reverse dark current density j = (4–9) × 10–3 A/cm2 at Urev = 1.0–2.0 V, and high-speed performance (response time 5–10 ns).