Tianming Zhou

Theoretical analysis of the Auger mechanism in a GaInAsSb infrared photovoltaic detector

A theoretical analysis of the Auger mechanism in a GaInAsSb infrared photovoltaic detector is reported. The considerations are carried out for near-room temperature and 2.5-mm wavelength. The results show that the Auger mechanism can be suppressed by optimizing the material parameters. Thus, the performance of such detectors can be improved.

Numerical analysis of the detectivity in n(+)-n-p and p(+)-p-n GaInAsSb infrared detectors

Abstract In this paper, the detectivity for n + –n–p and p + –p–n GaInAsSb infrared detectors in both the front- and backside illuminated cases are calculated and analyzed, respectively. The influence of the carrier concentration and width in each layer, as well as the surface recombination velocities at different surfaces of the detectors are considered. It is indicated that high R 0 A dose not guarantee the high detectivity because the quantum efficiency combines with the R 0 A to determine the behavior of D *. On the base of the calculations, it is observed that the different material parameters are required for the optimum D * in the different structures with the different directions of the light injected.

Analysis of the product and detectivity in a GaInAsSb infrared photovoltaic detector

In this paper a theoretical analysis of the product and the detectivity in a GaInAsSb infrared photovoltaic detector is reported, dependent on the four fundamental kinds of noise mechanism and the quantum efficiency. The considerations are carried out for near room temperature and m wavelength. The analytical results show that the noise mechanisms can be reduced, and correspondingly the performance of such detectors can be improved.

METALORGANIC CHEMICAL-VAPOR-DEPOSITION OF GAXIN1-XSB TERNARY ALLOYS

Metalorganic chemical vapor deposition (MOCVD) of ternary GaxIn1−xSb alloys on GaSb and GaAs substrates has been investigated at atmospheric pressure, using TMGa, TMIn and TMSb as source materials. The optimized growth parameters obtained by experiment were a growth temperature of 600°C and a vapor IIIV ratio of 0.4. It was found that the growth temperature was a key growth parameter for surface morphology and crystalline quality of the GaxIn1−xSb epilayer. The influence of the growth temperature on the Ga solid composition was previously explained. The Ga solid composition was proportional to the Ga vapor composition and vapor IIIV ratio, respectively. The Ga distribution coefficient was found to be 1.06 under the optimized growth parameters and decreased with decreasing growth temperature. The results of the Hall measurement for GaxIn1−xSb alloys were presented with p-type background of the epilayers.

Effect of material parameters on the quantum efficiency of GaInAsSb detectors

Abstract In this paper, a theoretical study of the effect of material parameters on the quantum efficiency of a homogeneous GaInAsSb infrared photovolatic detector is presented. The considerations are carried out for the near room temperature and 2.5 μ m wavelength. The calculated results show that the quantum efficiency depends strongly on the carrier concentrations in the n- and p-regions. In addition, the absorption coefficient, the surface recombination velocities and the widths of the two regions also effect the quantum efficiency.

The analysis of the performance for P-p-n and N-n-p hetero- and homojunction GaSb/Ga0.8In0.2As0.19Sb0.81 photodetectors

In this paper, the performance is analyzed for the P 1 -p 2 -n and N 1 -n 2 -p hetero- and homojunction GaSb/Ga 0.8 In 0.2 As 0.19 Sb 0.81 photodetectors operated at 300 K, based on the incident wavelength and the parameters of GaSb and Ga 0.8 In 0.2 As 0.19 Sb 0.81 The analyzed results show that the detectivity is much higher with the light incident first through the p-type than first through the n-type Ga 0.8 In 0.2 As 0.19 Sb 0.81 for both structures. In addition, the carrier concentration of GaSb should be as low as possible to reduce the tunneling noise through the P 1 -p 2 and N 1 -n 2 heterojunctions. With the same condition for the two structures, the N 1 -n 2 -p structure is more advantage than the P 1 -p 2 -n structure because the high P 1 -p 2 heterojunction recombination velocity increases the Auger and radiative noise mechanisms, which limit the performance of photodetectors.

Growth of GaSb-rich and InAs-rich GaInAsSb alloys on GaSb substrates by MOCVD

MOCVD growth and characterization of GaSb-rich and InAs-rich GaInAsSb on GaSb substrates was investigated. The surface of InAs-rich GaInAsSb epilayers showed morphological features very different from those on GaSb-rich films. Solid compositions of Ga1-xInxAsySb1-y films were dependent on growth temperature and the input source ratios, such as Ga/III ratio and Sb/V ratio. Unintentionally doped InAs-rich GaInAsSb showed n-type conduction, and GaSb-rich samples were p-type. A room temperature electron mobility of 5000 cm2v-1s-1 with electron concentration of 3.6×1017cm-3 for InAs-rich films was obtained. On the other hand, a hole mobility of 360 cm2v-1s-1 with a hole concentration of 1×1017cm-3 for GaSb-rich samples was achieved.

Growth and characterization of InAs-rich GaInAsSb alloys on GaSb substrates by MOCVD

MOCVD growth and characterization of InAs-rich GaInAsSb on GaSb substrates was investigated. High quality mirror-like surfaces with a minimum lattice mismatch of 0.4% was obtained. The surface of InAs-rich GaInAsSb epilayer shows morphological features much different from that of GaSb-rich films. Solid compositions of InAs-rich films were dependent on growth temperature. InAs-rich GaInAsSb shows n-type conduction, which is the opposite of GaSb-rich samples. A room temperature electron mobility of 5000 cm(2)/V.s with electron concentration of 3.6 x 10(17) cm(-3) was obtained