Midwave infrared InAs/GaSb superlattice photodiode with a dopant-free p–n junction

Abstract

Midwave infrared (MWIR) InAs/GaSb superlattice (SL) photodiode with a dopant-free p-n junction was fabricated by molecular beam epitaxy on GaSb substrate. Depending on the thickness ratio between InAs and GaSb layers in the SL period, the residual background carriers of this adjustable material can be either n-type or p-type. Using this flexibility in residual doping of the SL material, the p-n junction of the device is made with different nonintentionally doped (nid) SL structures. The SL photodiode processed shows a cutoff wavelength at 4.65µm at 77K, residual carrier concentration equal to 1.75x10 15 cm-3 , dark current density as low as 2.8x10-8 A/cm 2 at 50 mV reverse bias and R0A product as high as 2x10 6 .cm 2. The results obtained demonstrate the possibility to fabricate a SL pin photodiode without intentional doping the pn junction. Highlights :-MWIR SL photodiode was made using the flexibility properties of InAs/GaSb Superlattice-MWIR SL photodiode was made without intentional doping the pn junction-Electrical and electro-optical characterizations of MWIR pin SL photodiode made of dopant-free p-n junction have been reported

Investigation of a near mid-gap trap energy level in mid-wavelength infrared InAs/GaSb type-II superlattices

“…Some later reports, which are mostly based on Hall effect measurements, show the changeover for not intentially doped (n.i.d.) structures that are very similar to our SPD MWIR samples for both 120 and 190 K [19,[30][31][32]. However, as was pointed by Koncewicz et al [20], despite the change of conductivity character in undoped SL obtained from Hall mobility analysis, no changes in the sign of the Hall effect were reported for lower T. An explanation of such conduction behaviour was proposed by Rao et al [33], where the conductivity type change of an MWIR InAs 8ML /GaSb 8ML sample at about 120 K was interpreted as a change between the dominant contribution of a few near-surface SL wells, with Figure 1.…”

Fabrication of Mg2Si pn-junction photodiode with shallow mesa-structure and ring electrode

“…Figure 5 (a) shows J-V characteristics of shallow mesa-type Mg2Si PD (ID = 400 μm) between 100 K and 350 K. The leakage current in reverse bias decreased rapidly with decreasing the temperature. The current density at -3 V reached to about 9 × 10 -4 A/cm 2 at 100 K. Figure 5 (b) shows an Arrhenius plot of the saturation current density at -1 V. The saturation current density aligned two slopes, indicating that the PD may work in generation limited condition above about 250 K [11,12].…”

Identification of a limiting mechanism in GaSb-rich superlattice midwave infrared detector

“…More details on such measurements can be found in Ref. 27. The background carrier concentration was extracted from the capacitance-voltage characteristic of a GaSb-rich SL p-i-n diode.…”